Plaintext recovery and record forgery via nonce reuse
Published Aug 28, 2026 · Updated Aug 28, 2026
AES-GCM nonce reuse in wolfSSL wolfEngine 0.9.0 through 1.4.0 allows attackers to recover plaintext and forge TLS records. The TLS 1.2 and DTLS 1.2 AES-GCM record path generates the 8-byte explicit nonce when the write key is set but never increments it, encrypting every record in a connection under the same key-nonce pair. Exposure requires AES-GCM traffic and access to its encrypted records; AES-CCM, TLS 1.3, and non-TLS cipher use are unaffected.
Summary
What happened
AES-GCM nonce reuse in wolfSSL wolfEngine 0.9.0 through 1.4.0 allows attackers to recover plaintext and forge TLS records. The TLS 1.2 and DTLS 1.2 AES-GCM record path generates the 8-byte explicit nonce when the write key is set but never increments it, encrypting every record in a connection under the same key-nonce pair. Exposure requires AES-GCM traffic and access to its encrypted records; AES-CCM, TLS 1.3, and non-TLS cipher use are unaffected.
The record
- CVE
- CVE-2026-81020
- Published
- Aug 28, 2026
- Updated
- Aug 28, 2026
- Vendor
- wolfSSL
- Product
- wolfEngine
- Classifications
- T1040
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Aug 28, 2026CVE publishedPublication date reported by the CVE source.
- Aug 28, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
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- Affected versionversion=0 <=1.4.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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