Description
joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.6, joserfc compact JWS deserialization calls bytes.split() before enforcing the existing aggregate segment-size limits. When attacker-controlled compact serialization bytes reach deserialize_compact(), the split creates copies of the header, payload, and signature segments before ExceededSizeError rejects them, causing an additional allocation approximately proportional to the supplied token. Requests that exhaust available process memory can therefore cause an availability failure even though signature verification fails. This issue is fixed in version 1.7.6.
Published: 2026-10-29
Score: 6.9 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

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Remediation

No vendor fix or workaround currently provided.

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Tracking

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Advisories
Source ID Title
Github GHSA Github GHSA GHSA-9pg5-8c7x-5hfx joserfc: Compact JWS size guard allocates attacker-controlled segments before rejection
History

Fri, 30 Oct 2026 18:30:00 +0000

Type Values Removed Values Added
Metrics ssvc

{'options': {'Automatable': 'yes', 'Exploitation': 'poc', 'Technical Impact': 'partial'}, 'version': '2.0.3'}


Fri, 30 Oct 2026 12:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-770
References
Metrics threat_severity

None

cvssV3_1

{'score': 5.3, 'vector': 'CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L'}

threat_severity

Moderate


Thu, 29 Oct 2026 22:30:00 +0000

Type Values Removed Values Added
First Time appeared Authlib
Authlib joserfc
Vendors & Products Authlib
Authlib joserfc

Thu, 29 Oct 2026 21:45:00 +0000

Type Values Removed Values Added
Description joserfc is a Python library that provides an implementation of several JSON Object Signing and Encryption (JOSE) standards. Prior to 1.7.6, joserfc compact JWS deserialization calls bytes.split() before enforcing the existing aggregate segment-size limits. When attacker-controlled compact serialization bytes reach deserialize_compact(), the split creates copies of the header, payload, and signature segments before ExceededSizeError rejects them, causing an additional allocation approximately proportional to the supplied token. Requests that exhaust available process memory can therefore cause an availability failure even though signature verification fails. This issue is fixed in version 1.7.6.
Title joserfc: Compact JWS size guard allocates attacker-controlled segments before rejection
Weaknesses CWE-400
References
Metrics cvssV4_0

{'score': 6.9, 'vector': 'CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N'}


cve-icon MITRE

Status: PUBLISHED

Assigner: GitHub_M

Published:

Updated: 2026-10-30T17:05:38.184Z

Reserved: 2026-10-29T18:50:28.065Z

Link: CVE-2026-119284

cve-icon Vulnrichment

Updated: 2026-10-30T17:05:32.350Z

cve-icon NVD

Status : Deferred

Published: 2026-10-29T22:17:01.210

Modified: 2026-10-30T17:17:17.850

Link: CVE-2026-119284

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-10-29T21:33:16Z

Links: CVE-2026-119284 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-10-30T14:00:17Z

Weaknesses