Vulnerability · Published May 13, 2026 · Assigned by CPANSec

CVE-2026-8463Crypt::Argon2 versions from 0.017 before 0.031 for Perl perform a heap out-of-bounds read in argon2_verify on empty encoded input

Medium 5.3

In plain English

A medium-severity security flaw in Crypt::Argon2 from LEONT. There are no confirmed reports of exploitation so far. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 26% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)5.3Medium
Exploit odds (30 days)0.3%top 74.1% of all CVEs
Exploited in the wildNo reportsCISA SSVC: none
Attack toolingNoneno public tooling known

Official description

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.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Alpine:v3.24perl-crypt-argon20.031-r0ALPINE-CVE-2026-8463
Debian:12libcrypt-argon2-perlno fix listedDEBIAN-CVE-2026-8463
Debian:13libcrypt-argon2-perlno fix listedDEBIAN-CVE-2026-8463
Debian:14libcrypt-argon2-perl0.031-1DEBIAN-CVE-2026-8463
Ubuntu:24.04:LTSlibcrypt-argon2-perlno fix listedUBUNTU-CVE-2026-8463
Ubuntu:25.10libcrypt-argon2-perlno fix listedUBUNTU-CVE-2026-8463
Ubuntu:26.04:LTSlibcrypt-argon2-perlno fix listedUBUNTU-CVE-2026-8463
Ubuntu:26.10libcrypt-argon2-perlno fix listedUBUNTU-CVE-2026-8463

Affected products (as reported)

VendorProductVersions
LEONT Crypt::Argon2 0.017 – before 0.031

Weakness: CWE-126, CWE-191 · Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L

References