Oj: Negative-Size memcpy in Oj::Parser create_id Attribute Handling
33Vexday Risk Score
No sign of exploitation. It has a public proof of concept.
ssvc Attendcvss 6.3epss 0.4%
from disclosure to weapon25 days
Published on NVDJun 30
1st PoC+25d
exploitation probability
0.4%top 64% of all CVEs
observed exploitation
nono source reports it
1 public exploit(s)
Oj (Optimized JSON) is a JSON parser and Object marshaller packaged as a Ruby gem. In versions prior to 3.17.2, when in usual mode with create_id enabled, Oj::Parser#parse is vulnerable to heap corruption via a negative-size memcpy. When a JSON object key is exactly 65,535 bytes long, an integer truncation in form_attr (usual.c:63) converts the length to -1 before passing it to memcpy. This causes memcpy to copy SIZE_MAX bytes (interpreted as a huge size_t), corrupting heap memory and crashing the process. The issue has been fixed in version 3.17.2.
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N
Affected products
ohler55 · ojpublic PoCs found — 1
githubgithub.com/HORKimhab/CVE-2026-54900★ 0⚠ Public resources, to assess the exposure of systems you control or are authorized to test. Test only with authorization.