CVE-2026-13758 Affecting libcryptx-perl package, versions *
Threat Intelligence
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
Do your applications use this vulnerable package?
In a few clicks we can analyze your entire application and see what components are vulnerable in your application, and suggest you quick fixes.
Test your applications- Snyk IDSNYK-DEBIAN13-LIBCRYPTXPERL-17708344
- published30 Jun 2026
- disclosed29 Jun 2026
Introduced: 29 Jun 2026
CVE-2026-13758 (opens in a new tab)How to fix?
There is no fixed version for Debian:13 libcryptx-perl.
NVD Description
Note: Versions mentioned in the description apply only to the upstream libcryptx-perl package and not the libcryptx-perl package as distributed by Debian.
See How to fix? for Debian:13 relevant fixed versions and status.
CryptX versions before 0.088_001 for Perl compare AEAD authentication tags in non-constant time in the streaming decrypt_done path.
The decrypt_done($tag) form compares it against the computed tag with memNE (memcmp() != 0), which short-circuits on the first differing byte, so its run time depends on the number of matching leading bytes. This affects all five AEAD modes: GCM, CCM, ChaCha20Poly1305, EAX and OCB. The one-shot *_decrypt_verify helpers are unaffected; they verify the tag inside libtomcrypt with a constant-time comparison.
The timing difference is a tag-verification oracle. An attacker who can submit many candidate tags for the same nonce, ciphertext and associated data while measuring the timing precisely enough may recover the expected tag byte by byte and forge a message that verifies.