CVE Explorer
CVE-2026-44660
UltraJSON is a fast JSON encoder and decoder written in pure C with bindings for Python 3.7+. Prior to 5.12.1, when ujson.dump() writes to a file-like object and the write operation raises an exception, the serialized JSON string object is not decremented, leaking memory. Each failed write operation leaks the full size of the serialized payload. This vulnerability is fixed in 5.12.1.
Known exploited
Not asserted
Disputed
No
Stale source
No
Conflicts
0
Affected products and versions
1 source assertion{"product":"ultrajson","vendor":"ultrajson","versions":[{"status":"affected","version":"< 5.12.1"}]}
- cve_program_cvelist_v5affectedurn:baitaphish:normalized-source-record:v2:74c585380ddd0036ebe1ea8e81c1a6339d3d058bb1e71876ebf4b7ca81c74e4d · sha256:3d18ef68edecc23a… · /containers/cna/affected/0
Provider-owned CVSS observations
1 source assertion{"metric":{"attackComplexity":"LOW","attackRequirements":"NONE","attackVector":"NETWORK","baseScore":8.7,"baseSeverity":"HIGH","privilegesRequired":"NONE","subAvailabilityImpact":"NONE","subConfidentialityImpact":"NONE","subIntegrityImpact":"NONE","userInteraction":"NONE","vectorString":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0","vulnAvailabilityImpact":"HIGH","vulnConfidentialityImpact":"NONE","vulnIntegrityImpact":"NONE"},"metric_type":"cvssV4_0"}
- cve_program_cvelist_v5cvssurn:baitaphish:normalized-source-record:v2:74c585380ddd0036ebe1ea8e81c1a6339d3d058bb1e71876ebf4b7ca81c74e4d · sha256:3d18ef68edecc23a… · /containers/cna/metrics/0/cvssV4_0
CWE assertions
1 source assertion{"cweId":"CWE-401","description":"CWE-401: Missing Release of Memory after Effective Lifetime","lang":"en","type":"CWE"}
- cve_program_cvelist_v5cweurn:baitaphish:normalized-source-record:v2:74c585380ddd0036ebe1ea8e81c1a6339d3d058bb1e71876ebf4b7ca81c74e4d · sha256:3d18ef68edecc23a… · /containers/cna/problemTypes/0/descriptions/0
Source references
4 source assertions{"name":"https://github.com/ultrajson/ultrajson/commit/82af1d0ac01d09aa40c887b460d44b9d9f4bccd9","tags":["x_refsource_MISC"],"url":"https://github.com/ultrajson/ultrajson/commit/82af1d0ac01d09aa40c887b460d44b9d9f4bccd9"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:74c585380ddd0036ebe1ea8e81c1a6339d3d058bb1e71876ebf4b7ca81c74e4d · sha256:3d18ef68edecc23a… · /containers/cna/references/1
{"name":"https://github.com/ultrajson/ultrajson/releases/tag/5.12.1","tags":["x_refsource_MISC"],"url":"https://github.com/ultrajson/ultrajson/releases/tag/5.12.1"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:74c585380ddd0036ebe1ea8e81c1a6339d3d058bb1e71876ebf4b7ca81c74e4d · sha256:3d18ef68edecc23a… · /containers/cna/references/2
{"name":"https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg","tags":["x_refsource_CONFIRM"],"url":"https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:74c585380ddd0036ebe1ea8e81c1a6339d3d058bb1e71876ebf4b7ca81c74e4d · sha256:3d18ef68edecc23a… · /containers/cna/references/0
{"tags":["exploit"],"url":"https://github.com/ultrajson/ultrajson/security/advisories/GHSA-c38f-wx89-p2xg"}
- cve_program_cvelist_v5referenceurn:baitaphish:normalized-source-record:v2:74c585380ddd0036ebe1ea8e81c1a6339d3d058bb1e71876ebf4b7ca81c74e4d · sha256:3d18ef68edecc23a… · /containers/adp/0/references/0
Attribution and limitations
- CVE Program CVEList V5: Reproduce the MITRE copyright designation and CVE license in copies. Source →
Provider severity values are preserved separately. Baitaphish does not convert them into a risk rating, infer affected products, or treat EPSS as observed exploitation.