CVE-2026-81020
HIGHDescription
wolfEngine before 1.4.1 generates the 8-byte explicit AES-GCM nonce once when the TLS write key is set and never increments it per record. As a result every TLS 1.2 and DTLS 1.2 AES-GCM record within a connection is encrypted under an identical key and nonce pair. Reusing a GCM key and nonce discloses the keystream (the XOR of two ciphertexts equals the XOR of their plaintexts, so one known record recovers the others) and leaks the GHASH authentication key, enabling authentication tag forgery. AES-CCM, TLS 1.3, and non-TLS use of the cipher are not affected.
How to fix
TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works
Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.
CVSS v3 Vector
Exploitability
Impact
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
Exploit Intelligence
Low risk: more likely to be exploited than 30% of all known CVEs.
References
Related Vulnerabilities
Other CWE-323 vulnerabilities, ordered by exploit likelihood. View all
| CVE | Severity | CVSS | EPSS | Exploited | Fix |
|---|---|---|---|---|---|
| CVE-2017-13082 | High | 8.1 | 4.6% | - | Fix |
| CVE-2026-49952 | Critical | 9.1 | 3.7% | - | - |
| CVE-2017-7902 | Critical | 9.8 | 2.6% | - | - |
| CVE-2017-13080 | Medium | 5.3 | 2.3% | - | Fix |
| CVE-2017-13084 | Medium | 6.8 | 2.2% | - | - |
| CVE-2017-13079 | Medium | 5.3 | 2.1% | - | Fix |
Common questions
How do I fix CVE-2026-81020?
Upgrade wolfengine to 1.4.1 or later.
Is CVE-2026-81020 being actively exploited?
Not that we know of. CVE-2026-81020 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.38% is the estimated probability that it will be exploited in the next 30 days. That is higher than 30% of all scored CVEs.
How severe is CVE-2026-81020?
CVE-2026-81020 has a CVSS v3 base score of 7.4, rated high. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.
What does CVE-2026-81020 affect?
Published advisories record a fix for wolfengine (NVD). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.
Embed a live status badge for CVE-2026-81020
Markdown
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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-09-29.