Search
Find a vulnerability
Search criteria
ⓘ
Use this form to refine search results.
Full-text search supports keyword queries with ranking and filtering.
You can combine vendor, product, and sources to narrow results.
Enable “Apply ordering” to sort by date instead of relevance.
2 vulnerabilities found for hpack by python-hyper
CVE-2026-59980 (GCVE-0-2026-59980)
Vulnerability from nvd – Published: 2026-09-23 22:07 – Updated: 2026-09-24 13:25
VLAI
EPSS
VEX
Title
hpack: Unbounded variable integer decoding can cause run-away computation on malformed input
Summary
hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of `0xFF` values to prevent malicious use.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-24 13:24 UTC
CWE
- CWE-400 - Uncontrolled Resource Consumption
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/python-hyper/hpack/security/ad… | x_refsource_CONFIRM |
| https://github.com/python-hyper/hpack/commit/8cfb… | x_refsource_MISC |
| https://cs.opensource.google/go/x/net/+/master:ht… | x_refsource_MISC |
| https://docs.rs/http2/0.5.19/src/http2/hpack/deco… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| python-hyper | hpack |
Affected:
< 4.2.0
|
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-59980",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-24T13:24:31.887152Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-09-24T13:25:08.900Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "hpack",
"vendor": "python-hyper",
"versions": [
{
"status": "affected",
"version": "\u003c 4.2.0"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of `0xFF` values to prevent malicious use."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 6.3,
"baseSeverity": "MEDIUM",
"privilegesRequired": "NONE",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "LOW",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-400",
"description": "CWE-400: Uncontrolled Resource Consumption",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-23T22:07:35.095Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/python-hyper/hpack/security/advisories/GHSA-8v8h-hg4w-mvq2",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/python-hyper/hpack/security/advisories/GHSA-8v8h-hg4w-mvq2"
},
{
"name": "https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c"
},
{
"name": "https://cs.opensource.google/go/x/net/+/master:http2/hpack/hpack.go;l=468;drc=8e2b117aee74f6b86c207a808b0255de45c0a18a",
"tags": [
"x_refsource_MISC"
],
"url": "https://cs.opensource.google/go/x/net/+/master:http2/hpack/hpack.go;l=468;drc=8e2b117aee74f6b86c207a808b0255de45c0a18a"
},
{
"name": "https://docs.rs/http2/0.5.19/src/http2/hpack/decoder.rs.html#403",
"tags": [
"x_refsource_MISC"
],
"url": "https://docs.rs/http2/0.5.19/src/http2/hpack/decoder.rs.html#403"
}
],
"source": {
"advisory": "GHSA-8v8h-hg4w-mvq2",
"discovery": "UNKNOWN"
},
"title": "hpack: Unbounded variable integer decoding can cause run-away computation on malformed input"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-59980",
"datePublished": "2026-09-23T22:07:35.095Z",
"dateReserved": "2026-07-07T19:41:00.004Z",
"dateUpdated": "2026-09-24T13:25:08.900Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
CVE-2026-59980 (GCVE-0-2026-59980)
Vulnerability from cvelistv5 – Published: 2026-09-23 22:07 – Updated: 2026-09-24 13:25
VLAI
EPSS
VEX
Title
hpack: Unbounded variable integer decoding can cause run-away computation on malformed input
Summary
hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of `0xFF` values to prevent malicious use.
Severity
SSVC
Exploitation: none
Automatable: no
Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-24 13:24 UTC
CWE
- CWE-400 - Uncontrolled Resource Consumption
Assigner
References
4 references
| URL | Tags |
|---|---|
| https://github.com/python-hyper/hpack/security/ad… | x_refsource_CONFIRM |
| https://github.com/python-hyper/hpack/commit/8cfb… | x_refsource_MISC |
| https://cs.opensource.google/go/x/net/+/master:ht… | x_refsource_MISC |
| https://docs.rs/http2/0.5.19/src/http2/hpack/deco… | x_refsource_MISC |
Impacted products
1 product
| Vendor | Product | Version | |
|---|---|---|---|
| python-hyper | hpack |
Affected:
< 4.2.0
|
{
"containers": {
"adp": [
{
"metrics": [
{
"other": {
"content": {
"id": "CVE-2026-59980",
"options": [
{
"Exploitation": "none"
},
{
"Automatable": "no"
},
{
"Technical Impact": "partial"
}
],
"role": "CISA Coordinator",
"timestamp": "2026-09-24T13:24:31.887152Z",
"version": "2.0.3"
},
"type": "ssvc"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-09-24T13:25:08.900Z",
"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"shortName": "CISA-ADP"
},
"title": "CISA ADP Vulnrichment"
}
],
"cna": {
"affected": [
{
"product": "hpack",
"vendor": "python-hyper",
"versions": [
{
"status": "affected",
"version": "\u003c 4.2.0"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "hpack is an HTTP/2 Header Encoding for Python. Prior to version 4.2.0, unbounded variable integer decoding can cause run-away computation on malformed input leading to O(n^2) runtime, effectively blocking further processing with large enough unsanitized input. A fix is available in python-hyper/hpack v4.2.0 to restricted variable integer decoding to uint32 to prevent run-away computation. As a workaround, sanitize input to hpack decoder for long sequences of `0xFF` values to prevent malicious use."
}
],
"metrics": [
{
"cvssV4_0": {
"attackComplexity": "LOW",
"attackRequirements": "PRESENT",
"attackVector": "NETWORK",
"baseScore": 6.3,
"baseSeverity": "MEDIUM",
"privilegesRequired": "NONE",
"subAvailabilityImpact": "NONE",
"subConfidentialityImpact": "NONE",
"subIntegrityImpact": "NONE",
"userInteraction": "NONE",
"vectorString": "CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N",
"version": "4.0",
"vulnAvailabilityImpact": "LOW",
"vulnConfidentialityImpact": "NONE",
"vulnIntegrityImpact": "NONE"
}
}
],
"problemTypes": [
{
"descriptions": [
{
"cweId": "CWE-400",
"description": "CWE-400: Uncontrolled Resource Consumption",
"lang": "en",
"type": "CWE"
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-09-23T22:07:35.095Z",
"orgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"shortName": "GitHub_M"
},
"references": [
{
"name": "https://github.com/python-hyper/hpack/security/advisories/GHSA-8v8h-hg4w-mvq2",
"tags": [
"x_refsource_CONFIRM"
],
"url": "https://github.com/python-hyper/hpack/security/advisories/GHSA-8v8h-hg4w-mvq2"
},
{
"name": "https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c",
"tags": [
"x_refsource_MISC"
],
"url": "https://github.com/python-hyper/hpack/commit/8cfb02c547740e16dbfe7aba77bad84b297cec2c"
},
{
"name": "https://cs.opensource.google/go/x/net/+/master:http2/hpack/hpack.go;l=468;drc=8e2b117aee74f6b86c207a808b0255de45c0a18a",
"tags": [
"x_refsource_MISC"
],
"url": "https://cs.opensource.google/go/x/net/+/master:http2/hpack/hpack.go;l=468;drc=8e2b117aee74f6b86c207a808b0255de45c0a18a"
},
{
"name": "https://docs.rs/http2/0.5.19/src/http2/hpack/decoder.rs.html#403",
"tags": [
"x_refsource_MISC"
],
"url": "https://docs.rs/http2/0.5.19/src/http2/hpack/decoder.rs.html#403"
}
],
"source": {
"advisory": "GHSA-8v8h-hg4w-mvq2",
"discovery": "UNKNOWN"
},
"title": "hpack: Unbounded variable integer decoding can cause run-away computation on malformed input"
}
},
"cveMetadata": {
"assignerOrgId": "a0819718-46f1-4df5-94e2-005712e83aaa",
"assignerShortName": "GitHub_M",
"cveId": "CVE-2026-59980",
"datePublished": "2026-09-23T22:07:35.095Z",
"dateReserved": "2026-07-07T19:41:00.004Z",
"dateUpdated": "2026-09-24T13:25:08.900Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}