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Advisory record · GHSA-2cw7-v8ff-p88r

Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle

CVSS 6.3 MediumEPSS 0.0041 · 35th percentile

Published by the GitHub Advisory Database at 19 Jun 2026, 19:34 UTC. agentprime has not analysed this yet, so whether it affects any app is not known.

PackageEcosystemAffectedFixed in
ojRubyGems<3.17.23.17.2
Identifiers
GHSA-2cw7-v8ff-p88r · CVE-2026-54899
Weakness (CWE)
CWE-416
Tags
Published
19 Jun 2026
Updated
6 Oct 2026

Machine-written summary

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

Oj (the RubyGems package oj) is affected in versions before 3.17.2. Disabling symbol_keys on a reused Oj::Parser instance frees its key cache without clearing the pointer, so a later parse call can read freed memory, a heap use-after-free. The source does not describe what an attacker can achieve beyond this, and it does not say how an attacker would reach the parser. Upgrade to oj 3.17.2, which is the fixed version.

Written 3 Nov 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
6.3 Medium 4.0 CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:N/VA:L/SC:N/SI:N/SA:N CNA (GitHub_M)
  • CISA KEV Not listed.
  • EPSS 0.0041, the 35th percentile, on 5 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

  1. 31 Oct 2026, 14:21 UTC First seen by agentprime
  2. 31 Oct 2026, 14:21 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.