CVE-2021-4464 (GCVE-0-2021-4464)
Vulnerability from cvelistv5 – Published: 2025-11-12 22:09 – Updated: 2025-11-21 15:36
VLAI
EPSS
VEX
Title
FIberHome AN5506-04-FA / HG6245D Routers Remote Stack Overflow
Summary
FiberHome AN5506-04-FA firmware versions up to and including RP2631 and HG6245D prior to RP2602 contain a stack-based buffer overflow, as the HTTP service ('webs') fails to enforce maximum lengths for Cookie header values. When a cookie longer than 511 bytes is processed, a stack buffer is overrun, leading to a crash or potential control of execution flow.
Severity
SSVC
Exploitation: none
Automatable: yes
Technical Impact: total
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2025-11-13 14:30 UTC
CWE
- CWE-121 - Stack-based Buffer Overflow
Assigner
References
3 references
| URL | Tags |
|---|---|
| https://pierrekim.github.io/blog/2021-01-12-fiber… | technical-descriptionexploit |
| https://pierrekim.github.io/advisories/2021-fiber… | technical-descriptionexploit |
| https://www.vulncheck.com/advisories/fiberhome-ro… | third-party-advisory |
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| FiberHome | AN5506-04-FA |
Affected:
0 , ≤ RP2631
(custom)
cpe:2.3:o:fiberhome:an5506-04-fa_firmware:*:*:*:*:*:*:*:* |
||
| FiberHome | HG6245D |
Affected:
0 , < RP2602
(custom)
cpe:2.3:o:fiberhome:hg6245d_firmware:*:*:*:*:*:*:*:* |
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2021-4464",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-11-13T14:30:31.859197Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2025-11-13T14:35:47.050Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "AN5506-04-FA",
"vendor": "FiberHome",
"versions": [
{
"lessThanOrEqual": "RP2631",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unaffected",
"product": "HG6245D",
"vendor": "FiberHome",
"versions": [
{
"lessThan": "RP2602",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:fiberhome:an5506-04-fa_firmware:*:*:*:*:*:*:*:*",
"versionEndIncluding": "rp2631",
"versionStartIncluding": "0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
},
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:fiberhome:hg6245d_firmware:*:*:*:*:*:*:*:*",
"versionEndExcluding": "rp2602",
"versionStartIncluding": "0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "OR"
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Pierre Barre"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FiberHome AN5506-04-FA firmware versions up to and including RP2631 and HG6245D prior to RP2602 contain a stack-based buffer overflow, as the HTTP service (\u0027webs\u0027) fails to enforce maximum lengths for Cookie header values. When a cookie longer than 511 bytes is processed, a stack buffer is overrun, leading to a crash or potential control of execution flow. \u003cbr\u003e"
}
],
"value": "FiberHome AN5506-04-FA firmware versions up to and including RP2631 and HG6245D prior to RP2602 contain a stack-based buffer overflow, as the HTTP service (\u0027webs\u0027) fails to enforce maximum lengths for Cookie header values. When a cookie longer than 511 bytes is processed, a stack buffer is overrun, leading to a crash or potential control of execution flow."
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 9.3,
"baseSeverity": "CRITICAL",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-121",
"description": "CWE-121 Stack-based Buffer Overflow",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-11-21T15:36:02.534Z",
"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"shortName": "VulnCheck"
},
"references": [
{
"tags": [
"technical-description",
"exploit"
],
"url": "https://pierrekim.github.io/blog/2021-01-12-fiberhome-ont-0day-vulnerabilities.html#misc-remote-stack-overflow-an5506"
},
{
"tags": [
"technical-description",
"exploit"
],
"url": "https://pierrekim.github.io/advisories/2021-fiberhome-0x00-ont.txt"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.vulncheck.com/advisories/fiberhome-routers-remote-stack-overflow"
}
],
"source": {
"discovery": "UNKNOWN"
},
"timeline": [
{
"lang": "en",
"time": "2021-01-12T17:00:00.000Z",
"value": "Pierre Kim publicly discloses vulnerability."
}
],
"title": "FIberHome AN5506-04-FA / HG6245D Routers Remote Stack Overflow",
"x_generator": {
"engine": "vulncheck"
}
}
},
"cveMetadata": {
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"assignerShortName": "VulnCheck",
"cveId": "CVE-2021-4464",
"datePublished": "2025-11-12T22:09:20.835Z",
"dateReserved": "2025-11-12T21:24:45.845Z",
"dateUpdated": "2025-11-21T15:36:02.534Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2021-4464",
"date": "2026-09-21",
"epss": "0.02031",
"percentile": "0.79929"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "AN5506-04-FA",
"vendor": "FiberHome",
"versions": [
{
"lessThanOrEqual": "RP2631",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unaffected",
"product": "HG6245D",
"vendor": "FiberHome",
"versions": [
{
"lessThan": "RP2602",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"source": "disclosure@vulncheck.com"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "FiberHome AN5506-04-FA firmware versions up to and including RP2631 and HG6245D prior to RP2602 contain a stack-based buffer overflow, as the HTTP service (\u0027webs\u0027) fails to enforce maximum lengths for Cookie header values. When a cookie longer than 511 bytes is processed, a stack buffer is overrun, leading to a crash or potential control of execution flow."
}
],
"id": "CVE-2021-4464",
"lastModified": "2026-06-17T04:19:48.850",
"metrics": {
"cvssMetricV40": [
{
"cvssData": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"availabilityRequirement": "NOT_DEFINED",
"baseScore": 9.3,
"baseSeverity": "CRITICAL",
"confidentialityRequirement": "NOT_DEFINED",
"exploitMaturity": "NOT_DEFINED",
"integrityRequirement": "NOT_DEFINED",
"modifiedAttackComplexity": "NOT_DEFINED",
"modifiedAttackRequirements": "NOT_DEFINED",
"modifiedAttackVector": "NOT_DEFINED",
"modifiedPrivilegesRequired": "NOT_DEFINED",
"modifiedSubAvailabilityImpact": "NOT_DEFINED",
"modifiedSubConfidentialityImpact": "NOT_DEFINED",
"modifiedSubIntegrityImpact": "NOT_DEFINED",
"modifiedUserInteraction": "NOT_DEFINED",
"modifiedVulnAvailabilityImpact": "NOT_DEFINED",
"modifiedVulnConfidentialityImpact": "NOT_DEFINED",
"modifiedVulnIntegrityImpact": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"source": "disclosure@vulncheck.com",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2021-4464",
"options": [
{
"exploitation": "none"
},
{
"automatable": "yes"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-11-13T14:30:31.859197Z",
"version": "2.0.3"
}
}
]
},
"published": "2025-11-12T22:15:42.027",
"references": [
{
"source": "disclosure@vulncheck.com",
"url": "https://pierrekim.github.io/advisories/2021-fiberhome-0x00-ont.txt"
},
{
"source": "disclosure@vulncheck.com",
"url": "https://pierrekim.github.io/blog/2021-01-12-fiberhome-ont-0day-vulnerabilities.html#misc-remote-stack-overflow-an5506"
},
{
"source": "disclosure@vulncheck.com",
"url": "https://www.vulncheck.com/advisories/fiberhome-routers-remote-stack-overflow"
}
],
"sourceIdentifier": "disclosure@vulncheck.com",
"vulnStatus": "Deferred",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-121"
}
],
"source": "disclosure@vulncheck.com",
"type": "Secondary"
}
]
}
},
"redhat_vex": {
"current_release_date": "2025-11-13T23:08:29+00:00",
"cve": "CVE-2021-4464",
"id": "CVE-2021-4464",
"initial_release_date": "2021-01-01T00:00:00+00:00",
"product_status:known_not_affected": "1",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "FIberHome AN5506-04-FA / HG6245D Routers Remote Stack Overflow",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2021/cve-2021-4464.json",
"version": "3"
},
"vulnrichment": {
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2021-4464",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "yes"
},
{
"Technical Impact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-11-13T14:30:31.859197Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2025-11-13T14:30:34.032Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "AN5506-04-FA",
"vendor": "FiberHome",
"versions": [
{
"lessThanOrEqual": "RP2631",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unaffected",
"product": "HG6245D",
"vendor": "FiberHome",
"versions": [
{
"lessThan": "RP2602",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:fiberhome:an5506-04-fa_firmware:*:*:*:*:*:*:*:*",
"versionEndIncluding": "rp2631",
"versionStartIncluding": "0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
},
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:fiberhome:hg6245d_firmware:*:*:*:*:*:*:*:*",
"versionEndExcluding": "rp2602",
"versionStartIncluding": "0",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
],
"operator": "OR"
}
],
"credits": [
{
"lang": "en",
"type": "finder",
"value": "Pierre Barre"
}
],
"descriptions": [
{
"lang": "en",
"supportingMedia": [
{
"base64": false,
"type": "text/html",
"value": "FiberHome AN5506-04-FA firmware versions up to and including RP2631 and HG6245D prior to RP2602 contain a stack-based buffer overflow, as the HTTP service (\u0027webs\u0027) fails to enforce maximum lengths for Cookie header values. When a cookie longer than 511 bytes is processed, a stack buffer is overrun, leading to a crash or potential control of execution flow. \u003cbr\u003e"
}
],
"value": "FiberHome AN5506-04-FA firmware versions up to and including RP2631 and HG6245D prior to RP2602 contain a stack-based buffer overflow, as the HTTP service (\u0027webs\u0027) fails to enforce maximum lengths for Cookie header values. When a cookie longer than 511 bytes is processed, a stack buffer is overrun, leading to a crash or potential control of execution flow."
}
],
"metrics": [
{
"cvssV4_0": {
"Automatable": "NOT_DEFINED",
"Recovery": "NOT_DEFINED",
"Safety": "NOT_DEFINED",
"attackComplexity": "LOW",
"attackRequirements": "NONE",
"attackVector": "NETWORK",
"baseScore": 9.3,
"baseSeverity": "CRITICAL",
"exploitMaturity": "NOT_DEFINED",
"privilegesRequired": "NONE",
"providerUrgency": "NOT_DEFINED",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"valueDensity": "NOT_DEFINED",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "HIGH",
"vulnConfidentialityImpact": "HIGH",
"vulnIntegrityImpact": "HIGH",
"vulnerabilityResponseEffort": "NOT_DEFINED"
},
"format": "CVSS",
"scenarios": [
{
"lang": "en",
"value": "GENERAL"
}
]
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-121",
"description": "CWE-121 Stack-based Buffer Overflow",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2025-11-21T15:36:02.534Z",
"orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"shortName": "VulnCheck"
},
"references": [
{
"tags": [
"technical-description",
"exploit"
],
"url": "https://pierrekim.github.io/blog/2021-01-12-fiberhome-ont-0day-vulnerabilities.html#misc-remote-stack-overflow-an5506"
},
{
"tags": [
"technical-description",
"exploit"
],
"url": "https://pierrekim.github.io/advisories/2021-fiberhome-0x00-ont.txt"
},
{
"tags": [
"third-party-advisory"
],
"url": "https://www.vulncheck.com/advisories/fiberhome-routers-remote-stack-overflow"
}
],
"source": {
"discovery": "UNKNOWN"
},
"timeline": [
{
"lang": "en",
"time": "2021-01-12T17:00:00.000Z",
"value": "Pierre Kim publicly discloses vulnerability."
}
],
"title": "FIberHome AN5506-04-FA / HG6245D Routers Remote Stack Overflow",
"x_generator": {
"engine": "vulncheck"
}
}
},
"cveMetadata": {
"assignerOrgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
"assignerShortName": "VulnCheck",
"cveId": "CVE-2021-4464",
"datePublished": "2025-11-12T22:09:20.835Z",
"dateReserved": "2025-11-12T21:24:45.845Z",
"dateUpdated": "2025-11-21T15:36:02.534Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
}
}
Loading…
Loading…
Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
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.
Loading…
Loading…
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.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Loading…
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
Loading…