{"id":"CVE-2026-53720","title":"pymonocypher uses cython to wrap the Monocypher C library","summary":"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, t…","severity":"medium","cwe":["CWE-122","CWE-787","CWE-1284"],"vendor":"pymonocypher","product":"pymonocypher","affected":["pymonocypher < 4.0.2.8"],"patched":["pymonocypher 4.0.2.8"],"published":"2026-09-03","updated":"2026-09-09","sourceUpdated":"2026-09-09T21:09:13.080","source":"NVD","sourceUrl":"https://nvd.nist.gov/vuln/detail/CVE-2026-53720","references":[{"url":"https://github.com/jetperch/pymonocypher/commit/90ff5b13b13b5673c372e188f482d8c172e6ab86","label":"security-advisories@github.com"},{"url":"https://github.com/jetperch/pymonocypher/releases/tag/v4.0.2.8","label":"security-advisories@github.com"},{"url":"https://github.com/jetperch/pymonocypher/security/advisories/GHSA-8f95-v3jq-cj86","label":"security-advisories@github.com"},{"url":"https://github.com/advisories/GHSA-8f95-v3jq-cj86"}],"tags":["nvd","ghsa","pip"],"epss":0.00178,"epssPercentile":0.06564,"aliases":["GHSA-8f95-v3jq-cj86"],"ecosystem":"pip","ingestedAt":"2026-07-09T13:51:05.178Z","slug":"CVE-2026-53720","body":"## Overview\n\npymonocypher 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.\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.\n\n## Package advisory (CVE-2026-53720)\n\nAffected packages:\n\n- `pymonocypher < 4.0.2.8`\n\nPatched in:\n\n- `pymonocypher 4.0.2.8`\n\nSource: https://github.com/advisories/GHSA-8f95-v3jq-cj86","depth":"sunlit","depthScore":28,"depthScoreParts":{"impact":27.5,"likelihood":0,"exploitation":0,"ransomware":0},"changes":[]}