CVE-2026-8463

Crypt::Argon2 versions from 0.017 before 0.031 for Perl perform a heap out-of-bounds read in argon2_verify on empty encoded input. The auto-detect form of argon2_verify passes encoded_len - 1 as the length argument to memchr without checking that encoded_len is non-zero. When the encoded string is empty, the size_t subtraction underflows to SIZE_MAX and memchr scans adjacent heap memory looking for a '$' separator byte. A caller that invokes argon2_verify against a stored hash that may legitimately be empty (for example a placeholder row or a NULL column materialised as an empty string) reads out-of-bounds heap memory, which can crash the process or leak the position of an adjacent '$' byte into subsequent parsing.

CVSS 3.1

5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

EPSS

0.3% chance of exploitation in the next 30 days; higher than 25% of CVEs (scores of 2026-10-25)

CWEs

CWE-126, CWE-191

Published

2026-05-13

Modified

2026-10-26

Record from

the NVD, synced 2026-10-26

Affected

• leont:crypt\

References

• https://github.com/Leont/crypt-argon2/commit/92eac03ce63d541e0ead7ea5a89b9b67ce0c0e64.patch
• https://metacpan.org/release/LEONT/Crypt-Argon2-0.031/changes
• http://www.openwall.com/lists/oss-security/2026/05/13/4

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