CVE-2026-53720

medium

Description

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.

References

https://github.com/hextheshadow/PoC-Exploit

https://github.com/jetperch/pymonocypher/security/advisories/GHSA-8f95-v3jq-cj86

https://github.com/jetperch/pymonocypher/releases/tag/v4.0.2.8

https://github.com/jetperch/pymonocypher/commit/90ff5b13b13b5673c372e188f482d8c172e6ab86

Details

Source: Mitre, NVD

Published: 2026-09-03

Updated: 2026-09-03

Risk Information

CVSS v2

Base Score: 7.5

Vector: CVSS2#AV:N/AC:L/Au:N/C:P/I:P/A:P

Severity: High

CVSS v3

Base Score: 9.8

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: Critical

CVSS v4

Base Score: 5.1

Vector: 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

Severity: Medium

EPSS

EPSS: 0.00126