PT-2026-29863 · Unknown · Leancrypto

Programsurf + 1 · Published 2026-04-02 · Updated 2026-04-16 · CVE-2026-34610

Positive Technologies (AI Summary)

CVSS v3.1

5.9

Medium

Base vector

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

Name of the Vulnerable Software and Affected Versions leancrypto versions prior to 1.7.1

Description The leancrypto library, a cryptographic library focused on post-quantum cryptography, has an issue in the lc x509 extract name segment() function. A cast from size t to uint8 t when handling the Common Name (CN) length allows an attacker to craft a malicious certificate. By padding the CN with 256 bytes, an attacker can manipulate the cn size variable, effectively impersonating a victim's identity in PKCS#7 verification, certificate chain matching, and code signing.

Recommendations Update to version 1.7.1 or later.

Fix

Weakness Enumeration

CWE-681

Related Identifiers

CVE-2026-34610

OPENSUSE-SU-2026:10563-1

Affected Products

Leancrypto

References · 8

• https://github.com/smuellerDD/leancrypto/security/advisories/GHSA-636g-jxv4-v4gr · Vendor Advisory
• https://github.com/smuellerDD/leancrypto/commit/5cdcbe12bd6c3d6e87e969972a580b44a74c3a6a · Patch
• https://osv.dev/vulnerability/openSUSE-SU-2026:10563-1 · Vendor Advisory
• https://nvd.nist.gov/vuln/detail/CVE-2026-34610 · Security Note
• https://github.com/smuellerDD/leancrypto/releases/tag/v1.7.1 · Note
• https://twitter.com/CVEnew/status/2040128816635326591 · Twitter Post
• https://twitter.com/infoflowcloud/status/2040130150134661207 · Twitter Post
• https://suse.com/security/cve/CVE-2026-34610 · Note