CVE-2026-53720CWE-122CWE-1284CWE-787

CVE-2026-53720

published September 3, 2026

CVSS
5.1
EPSS
0%
Percentile
2.5
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS
5.1 · NONE
CVSS v4.0
5.1 · 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
EPSS
0.00126 · 2.5th percentile
Weaknesses
CWE-122 · Heap-based Buffer Overflow; CWE-1284 · Improper Validation of Specified Quantity in Input; CWE-787 · Out-of-bounds Write
Published
2026-09-03T20:17Z
References (3)
https://github.com/jetperch/pymonocypher/commit/90ff5b13b13b5673c372e188f482d8c172e6ab86 · [email protected]https://github.com/jetperch/pymonocypher/releases/tag/v4.0.2.8 · [email protected]https://github.com/jetperch/pymonocypher/security/advisories/GHSA-8f95-v3jq-cj86 · [email protected]
EPSS history
Timeline
  • 05 SEP 03:43Z
    EPSS moved — → 0%
    epss
  • 03 SEP 15:30Z
    pymonocypher: Potential heap buffer overflow on nb_blocks in argon2i_32 when provided buffer is too small
    cvelistv5