6.9

CVE-2026-119284: joserfc: Compact JWS size guard allocates attacker-controlled segments before rejection

Deferred
AliasesDEBIAN-CVE-2026-119284GHSA-9pg5-8c7x-5hfxCGA-fg29-299r-49f6
Published 29-10-2026Last modified 30-10-2026

Vulnerability summary

CVE-2026-119284 is a medium (CVSS 6.9) Uncontrolled Resource Consumption vulnerability in authlib joserfc. EPSS estimates a 0.19% chance of exploitation in the next 30 days, higher than 8.9% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 6.9, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.9/10
010
Medium · v4.0 (CVE.org)
EPSS score
0.19%
0%100%
Low · Change unavailable
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 29-10-2026
    PublishedVulnerability first disclosed.
  2. 30-10-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

7 scores · 7 sources · 1 version

EPSS trend

Probability

0.19%

Chance of exploitation in the next 30 days

Percentile

9%

Versus all other CVEs

30-day change

Change unavailable

Change unavailable

30-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard5 products
  • localstackAll versions (No fix recorded)
  • open-webuiAll versions (No fix recorded)
  • py3.12-airflow-3All versions (No fix recorded)
  • py3.13-airflow-3All versions (No fix recorded)
  • py3.14-airflow-3All versions (No fix recorded)
Authlib1 product
Debian1 product
  • joserfcAll versions (No fix recorded) | < 1.7.7-1
PyPI1 product
  • joserfc< 1.7.6
Ubuntu1 product
  • joserfcAll versions (No fix recorded)
Wolfi1 product
  • open-webuiAll versions (No fix recorded)

6 vendors · 10 products

References

9 links