{"id":"CVE-2026-53720","summary":"pymonocypher: Potential heap buffer overflow on nb_blocks in argon2i_32 when provided buffer is too small","details":"pymonocypher uses cython to wrap the Monocypher C library. Prior to version 4.0.2.8, the argon2i_32 implementation does not check the nb_blocks size. If the caller does not provide a sufficiently large buffer based on the API contract, then argon2i_32 will write past the end of the buffer and possibly corrupt the heap. This issue has been patched in version 4.0.2.8.","aliases":["GHSA-8f95-v3jq-cj86","PYSEC-2026-3000"],"modified":"2026-09-11T03:30:22.122126577Z","published":"2026-09-03T15:30:06.690Z","database_specific":{"cwe_ids":["CWE-122","CWE-1284","CWE-787"],"osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53720.json","cna_assigner":"GitHub_M"},"references":[{"type":"WEB","url":"https://github.com/jetperch/pymonocypher/releases/tag/v4.0.2.8"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/53xxx/CVE-2026-53720.json"},{"type":"ADVISORY","url":"https://github.com/jetperch/pymonocypher/security/advisories/GHSA-8f95-v3jq-cj86"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2026-53720"},{"type":"FIX","url":"https://github.com/jetperch/pymonocypher/commit/90ff5b13b13b5673c372e188f482d8c172e6ab86"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://github.com/jetperch/pymonocypher","events":[{"introduced":"0"},{"fixed":"90ff5b13b13b5673c372e188f482d8c172e6ab86"},{"fixed":"896a6bdd527e1cbf351ebbdd2f513296b49a7f95"}],"database_specific":{"source":["AFFECTED_FIELD","REFERENCES"],"extracted_events":[{"introduced":"0"},{"fixed":"4.0.2.8"}]}}],"versions":["v4.0.2.7","v4.0.2.6","v4.0.2.5","v4.0.2.4","v4.0.2.3","v3.1.3.2","v4.0.2.2","v4.0.2.1","v3.1.3.1","v3.1.0.0","v0.1.4","v0.1.3"],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-53720.json"}}],"schema_version":"1.9.0","severity":[{"type":"CVSS_V4","score":"CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N"}]}