Message forgery via non-constant-time tag comparison
Published Jun 29, 2026 · Updated Jun 29, 2026
Observable timing discrepancy in CryptX before 0.088_001 allows remote attackers to forge AEAD authentication tags via repeated timing measurements. Each streaming decrypt_done($tag) implementation compares the supplied and computed tags with memNE, whose memcmp call stops at the first differing byte and exposes the matching-prefix length through execution time. Exploitation requires many attempts using the same nonce, ciphertext, and associated data plus sufficiently precise timing, and a recovered tag authenticates a forged message.
Summary
What happened
Observable timing discrepancy in CryptX before 0.088_001 allows remote attackers to forge AEAD authentication tags via repeated timing measurements. Each streaming decrypt_done($tag) implementation compares the supplied and computed tags with memNE, whose memcmp call stops at the first differing byte and exposes the matching-prefix length through execution time. Exploitation requires many attempts using the same nonce, ciphertext, and associated data plus sufficiently precise timing, and a recovered tag authenticates a forged message.
The record
- CVE
- CVE-2026-13758
- Published
- Jun 29, 2026
- Updated
- Jun 29, 2026
- Vendor
- DCIT, a.s.
- Product
- CryptX
- Classifications
- CWE-208
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Jun 29, 2026CVE publishedPublication date reported by the CVE source.
- Jun 29, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=0 <0.088_001
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo