CVE-2026-54898: ohler55 oj · Use After Free
Affects ohler55 ojSource GCVE Database
Not known to be exploited · CVSS 2.1 Low : upgrade to 3.17.2 when convenient.
Data as of 26 Oct 2026, 17:16 UTC
- EPSS
- 0.2% chance of exploitation in 30 days – higher than 10% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
- Patch
- Available – fixed in 3.17.2
CVSS:4.0/AV:L/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 30 Jun 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.
What to do
Upgrade ohler55 oj to 3.17.2.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
RubyGemsojpkg:gem/ojOther threats | Affected
| Fixed in
|
Ubuntu 14.04 LTSruby-ojpkg:deb/ubuntu/ruby-oj?arch=source&distro=trustyOther threats | Affected
| Fixed in– |
Ubuntu 16.04 LTSruby-ojpkg:deb/ubuntu/ruby-oj?arch=source&distro=xenialOther threats | Affected
| Fixed in– |
Ubuntu 18.04 LTSruby-ojpkg:deb/ubuntu/ruby-oj?arch=source&distro=bionicOther threats | Affected
| Fixed in– |
Ubuntu 20.04 LTSruby-ojpkg:deb/ubuntu/ruby-oj?arch=source&distro=focalOther threats | Affected
| Fixed in– |
Ubuntu 22.04 LTSruby-ojpkg:deb/ubuntu/ruby-oj?arch=source&distro=jammyOther threats | Affected
| Fixed in– |
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to Oj version 3.17.2 or later, where this vulnerability is fixed. No other mitigation is indicated by the vendor advisory.
Description
CVE-2026-54898 is a use-after-free vulnerability in the Oj Ruby gem for JSON parsing, affecting versions prior to 3.17.2. The flaw occurs when a SAJ/SAJ2 callback mutates the input JSON string during parsing, causing the parser to hold a raw pointer to a string buffer that may be reallocated and freed. This issue is fixed in version 3.17.2.