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.
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
| Ecosystem | Package | Fixed in | Advisory |
|---|---|---|---|
| Alpine:v3.24 | perl-crypt-argon2 | 0.031-r0 | ALPINE-CVE-2026-8463 |
| Debian:12 | libcrypt-argon2-perl | no fix listed | DEBIAN-CVE-2026-8463 |
| Debian:13 | libcrypt-argon2-perl | no fix listed | DEBIAN-CVE-2026-8463 |
| Debian:14 | libcrypt-argon2-perl | 0.031-1 | DEBIAN-CVE-2026-8463 |
| Ubuntu:24.04:LTS | libcrypt-argon2-perl | no fix listed | UBUNTU-CVE-2026-8463 |
| Ubuntu:25.10 | libcrypt-argon2-perl | no fix listed | UBUNTU-CVE-2026-8463 |
| Ubuntu:26.04:LTS | libcrypt-argon2-perl | no fix listed | UBUNTU-CVE-2026-8463 |
| Ubuntu:26.10 | libcrypt-argon2-perl | no fix listed | UBUNTU-CVE-2026-8463 |
Affected products (as reported)
| Vendor | Product | Versions |
|---|---|---|
| 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