PT-2026-40603 · Leont+3 · Crypt::Argon2+2

Published 2026-05-13 · Updated 2026-06-05 · CVE-2026-8463

Positive Technologies (AI Summary)

CVSS v3.1

5.3

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions Crypt::Argon2 versions 0.017 through 0.030

Description A heap out-of-bounds read occurs in the argon2 verify() function when processing empty encoded input. The auto-detect form of argon2 verify() passes encoded len - 1 as the length argument to memchr() without verifying that encoded len is non-zero. If the encoded string is empty, the size t subtraction underflows to SIZE MAX, causing memchr() to scan adjacent heap memory for a '$' separator byte. This can lead to process crashes or the leakage of the position of an adjacent '$' byte during subsequent parsing when the function is invoked against an empty stored hash.

Recommendations Update to version 0.031.

Exploit

Fix

DoS

Integer Underflow

Buffer Over-read

Weakness Enumeration

CWE-191

CWE-126

Related Identifiers

CVE-2026-8463

Affected Products

Crypt::Argon2

Crypt

Libcrypt-Argon2-Perl

References · 18

• 🔥 https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/8xxx/CVE-2026-8463.json · Exploit
• https://github.com/Leont/crypt-argon2/commit/92eac03ce63d541e0ead7ea5a89b9b67ce0c0e64.patch · Patch
• https://osv.dev/vulnerability/UBUNTU-CVE-2026-8463 · Vendor Advisory
• https://ubuntu.com/security/CVE-2026-8463 · Vendor Advisory
• https://security-tracker.debian.org/tracker/CVE-2026-8463 · Vendor Advisory
• https://cve.org/CVERecord?id=CVE-2026-8463 · Security Note
• https://nvd.nist.gov/vuln/detail/CVE-2026-8463 · Security Note
• https://osv.dev/vulnerability/CVE-2026-8463 · Vendor Advisory
• https://osv.dev/vulnerability/DEBIAN-CVE-2026-8463 · Vendor Advisory
• https://github.com/Leont/crypt-argon2/commit/92eac03ce63d541e0ead7ea5a89b9b67ce0c0e64 · Note
• https://github.com/Leont/crypt-argon2 · Note
• https://twitter.com/threatcluster/status/2062885755098206525 · Twitter Post
• https://twitter.com/oss_security/status/2055156069354070184 · Twitter Post
• https://twitter.com/oss_security/status/2055156072151748904 · Twitter Post
• http://openwall.com/lists/oss-security/2026/05/13/4 · Note