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
Description
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.
INFO
Published Date :
June 29, 2026, 9:16 p.m.
Last Modified :
June 30, 2026, 2:16 p.m.
Remotely Exploit :
Yes !
Source :
9b29abf9-4ab0-4765-b253-1875cd9b441e
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS | 134c704f-9b21-4f2e-91b3-4a467353bcc0 | |||||
| CVSS 3.1 | LOW | 134c704f-9b21-4f2e-91b3-4a467353bcc0 |
Solution
- Update CryptX to version 0.088_001 or later.
- Use *_decrypt_verify helpers for tag verification.
- Ensure constant-time comparison for authentication tags.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-13758.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-13758 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-13758
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-13758 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-13758 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
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CVE Modified by 134c704f-9b21-4f2e-91b3-4a467353bcc0
Jun. 30, 2026
Action Type Old Value New Value Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:N/A:N Added SSVC {'id': 'CVE-2026-13758', 'role': 'CISA Coordinator', 'options': [{'exploitation': 'none'}, {'automatable': 'no'}, {'technicalImpact': 'partial'}], 'version': '2.0.3', 'timestamp': '2026-06-30T13:56:51.096991Z'} -
CVE Modified by af854a3a-2127-422b-91ae-364da2661108
Jun. 29, 2026
Action Type Old Value New Value Added Reference http://www.openwall.com/lists/oss-security/2026/06/29/19 -
New CVE Received by 9b29abf9-4ab0-4765-b253-1875cd9b441e
Jun. 29, 2026
Action Type Old Value New Value Added Affected [{'repo': 'https://github.com/DCIT/perl-CryptX', 'vendor': 'MIK', 'product': 'CryptX', 'versions': [{'status': 'affected', 'version': '0', 'lessThan': '0.088_001', 'versionType': 'custom'}], 'packageName': 'CryptX', 'programFiles': ['inc/CryptX_AuthEnc_GCM.xs.inc', 'inc/CryptX_AuthEnc_CCM.xs.inc', 'inc/CryptX_AuthEnc_ChaCha20Poly1305.xs.inc', 'inc/CryptX_AuthEnc_EAX.xs.inc', 'inc/CryptX_AuthEnc_OCB.xs.inc'], 'collectionURL': 'https://cpan.org/modules', 'defaultStatus': 'unaffected', 'programRoutines': [{'name': 'Crypt::AuthEnc::GCM::decrypt_done'}, {'name': 'Crypt::AuthEnc::CCM::decrypt_done'}, {'name': 'Crypt::AuthEnc::ChaCha20Poly1305::decrypt_done'}, {'name': 'Crypt::AuthEnc::EAX::decrypt_done'}, {'name': 'Crypt::AuthEnc::OCB::decrypt_done'}]}] Added Description 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. Added CWE CWE-208 Added Reference https://github.com/DCIT/perl-CryptX/commit/7e56347d420aaf43b2ee1586f4a230492ccf1642.patch Added Reference https://metacpan.org/release/MIK/CryptX-0.088_001/changes