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Medium 6.3Published Jun 30, 2026

CVE-2026-54899Oj: Use-After-Free in Oj::Parser Symbol Key Cache Toggle

Updated under an hour ago ()

Does this affect you?

It affects ohler55 oj. Add what you run to find out whether that includes you.

No exploitation reported and no EPSS estimate yet.

Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. Prior to version 3.17.2, disabling symbol_keys on a reused Oj::Parser instance triggers a heap use-after-free. When symbol_keys is toggled from true to false, opt_symbol_keys_set frees the internal key cache (cache_free) but does not clear the pointer. The next parse call reads from the freed cache via cache_intern, producing a use-after-free. This issue has been fixed in version 3.17.2.

CVSS
6.3 MEDIUM (v4.0, CNA)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
Weakness (CWE)
CWE-416
Known exploited
Not in CISA's KEV catalog
EPSS (exploitation in the next 30 days)
Not loaded for this CVE
Assigned by
GitHub_M
NVD analysis
Deferred
Record last updated
Jul 1, 2026
First seen by InfoSec Signals
Oct 9, 2026

Affected products

Affected products
ohler55 oj
ohler55:oj (from the name)
before 3.17.2
CNA record

References

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The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.

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