wolfEngine reuses the AES-GCM nonce on every TLS 1.2 / DTLS 1.2 record

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-81020
StatePUBLISHED
AssignerwolfSSL
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-08-28 16:18:28 UTC
Updated2026-09-01 20:56:59 UTC
DescriptionwolfEngine 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.

Risk And Classification

Primary CVSS: v3.1 7.4 HIGH from [email protected]

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

EPSS: 0.002370000 probability, percentile 0.145670000 (date 2026-09-02)

Problem Types: CWE-323 | CWE-323 CWE-323 Reusing a Nonce, Key Pair in Encryption

VersionSourceTypeScoreSeverityVector
3.1[email protected]Secondary7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N
3.1CNACVSS7.4HIGHCVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

CVSS v3.1 Breakdown

Attack Vector
Network
Attack Complexity
High
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
None

CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:N

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA WolfSSL Inc. WolfEngine affected 1.4.0 git Not specified

References

ReferenceSourceLinkTags
www.wolfssl.com/docs/security-vulnerabilities [email protected] www.wolfssl.com
CVE Program record CVE.ORG www.cve.org canonical
NVD vulnerability detail NVD nvd.nist.gov canonical, analysis

Vendor Comments And Credit

Discovery Credit

CNA: wolfSSL security team (en)

Additional Advisory Data

Solutions

CNA: Upgrade to wolfEngine 1.4.1, which increments the explicit nonce after each record. As an interim mitigation use AES-CCM or TLS 1.3 instead of TLS 1.2 / DTLS 1.2 AES-GCM.

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