CVE-2026-81341: wolfEngine reuses the AES-CCM nonce on TLS 1.2 / DTLS 1.2 records
Vulnerability summary
CVE-2026-81341 is a medium (CVSS 6.5) Reusing a Nonce, Key Pair in Encryption vulnerability in wolfssl inc. wolfengine. EPSS estimates a 0.32% chance of exploitation in the next 30 days, higher than 24.8% of scored vulnerabilities.
Not severe (CVSS 6.5, network access); no exploitation reported by the 5 checked sources
Source freshness unavailable
How is this decided?Timeline
- 28-08-2026PublishedVulnerability first disclosed.
- 28-08-2026Last modifiedVulnerability information updated.
Description
wolfEngine before 1.4.1 sources the explicit AES-CCM nonce for TLS 1.2 and DTLS 1.2 records from the record input buffer instead of the TLS sequence number carried in the additional authenticated data. Because the record layer leaves the explicit-nonce field for the cipher to populate, the value read is constant across records, so every AES-CCM record within a connection is encrypted under an identical key and nonce pair. Reusing a CCM key and nonce weakens confidentiality (identical keystream across records, so a known record recovers the others) and integrity (authentication tag forgery). Only wolfEngine is affected; wolfProvider is not. AES-GCM under wolfEngine is tracked separately. AES-CCM cipher suites are not enabled by default and must be explicitly selected, which limits exposure. TLS 1.3 and non-TLS use of the cipher are not affected.
CVSS metrics
2 scores · 2 sources · 1 version- NVDNIST6.5MediumCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:L/A:N
EPSS trend
Probability
0.32%
Chance of exploitation in the next 30 days
Percentile
25%
Versus all other CVEs
30-day change
No change 0.00 pp
From 0.32% on 04-10-2026
Known exploited
Compare KEV catalogsNot in the CISA KEV catalog.
Not in the ENISA CNW catalog.
Not in the CIRCL catalog.
Public exploits
0 foundNo public exploits indexed.
Weaknesses
CWE · root causeAffected systems
Known conditions: network-reachable, no authentication, no user interaction (CVSS vector). Other conditions: not stated in public data.
Wolfssl1 product
- wolfengine< 1.4.1
Wolfssl inc.1 product
- wolfengine≤ 1.4.0
2 vendors · 2 products
References
1 links- www.wolfssl.com/docs/security-vulnerabilities/Vendor Advisory