CVE-2026-13758

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 v3 3.7 LOW

3.7^/10

CVSS v3 : LOW

Vector :

Exploitability : 2.2 / Impact : 1.4

Attack Vector NETWORK

Attack Complexity HIGH

Privileges Required NONE

User Interaction NONE

Confidentiality Impact LOW

Integrity Impact NONE

Availability Impact NONE

Scope UNCHANGED

References

Link	Resource
https://github.com/DCIT/perl-CryptX/commit/7e56347d420aaf43b2ee1586f4a230492ccf1642.patch
https://metacpan.org/release/MIK/CryptX-0.088_001/changes
http://www.openwall.com/lists/oss-security/2026/06/29/19

Configurations

No configuration.

History

30 Jun 2026, 14:16

Type	Values Removed	Values Added
CVSS	v2 : ~~unknown~~ v3 : ~~unknown~~	v2 : unknown v3 : 3.7

29 Jun 2026, 23:16

Type	Values Removed	Values Added
References		() http://www.openwall.com/lists/oss-security/2026/06/29/19 -

29 Jun 2026, 21:16

Type	Values Removed	Values Added
New CVE

Information

Published : 2026-06-29 21:16

Updated : 2026-06-30 14:16

NVD link : CVE-2026-13758

Mitre link : CVE-2026-13758

CVE.ORG link : CVE-2026-13758

JSON object : View

Products Affected

No product.

CWE

CWE-208

Observable Timing Discrepancy

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