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Advisory record · GHSA-9pg5-8c7x-5hfx

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

CVSS 6.9 MediumEPSS 0.0019 · 8th percentile

Published by the GitHub Advisory Database at 30 Oct 2026, 14:54 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
joserfcPyPI<1.7.61.7.6
Identifiers
GHSA-9pg5-8c7x-5hfx · CVE-2026-119284
Weakness (CWE)
CWE-400
Tags
Published
30 Oct 2026
Updated
30 Oct 2026

Machine-written summary

Summary written by Claude Haiku from the source advisory. Not reviewed by a person.

GHSA-9pg5-8c7x-5hfx concerns joserfc, a PyPI package, in versions before 1.7.6. The compact JWS size guard calls split() on the input before checking segment sizes, so an attacker who can supply a large compact JWS can cause the library to allocate roughly one payload-sized copy before the size rejection occurs. The source gives no authentication requirement; the input is described as reaching deserialize_compact(). Upgrade to joserfc 1.7.6, which contains the fix.

Written 31 Oct 2026.

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

ScoreRatingCVSSVectorSource
6.9 Medium 4.0 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 CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0019, the 8th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:07 UTC First seen by agentprime
  2. 31 Oct 2026, 14:07 UTC Confirmed by OSV

Sources

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.