CVE-2026-13758: low-severity vulnerability in MIK CryptX
CryptX versions before 0.088_001 for Perl compare AEAD authentication tags in non-constant time in the streaming decrypt_done path
Published · Updated
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8Vexday Risk Score
No sign of exploitation. No public exploitation artifact known so far.
ssvc Trackcvss 3.7epss 0.4%
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.
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N
Affected products
MIK · CryptXRelated CVEs — MIK CryptX
In the same product, most dangerous first.
CVE-2025-40914CRITICALPerl CryptX before version 0.087 contains a dependency that may be susceptible to an integer overflowEPSS 0.5%CVE-2026-41565HIGHCryptX versions before 0.088_001 for Perl have a stack buffer overflow in four AEAD decrypt_verify helpersEPSS 0.5%CVE-2026-41564HIGHCryptX versions before 0.088 for Perl do not reseed the Crypt::PK PRNG state after forkingEPSS 0.4%CVE-2025-40912CRITICALCryptX for Perl before version 0.065 contains a dependency that may be susceptible to malformed unicodeEPSS 0.4%