CVE-2026-6986: Cesanta Mongoose GCM Authentication Tag tls_aes128.c mg_aes_gcm_decrypt signature verification
A security vulnerability has been detected in Cesanta Mongoose up to 7.20. This issue affects the function mgaesgcmdecrypt of the file /src/tlsaes128.c of the component GCM Authentication Tag Handler. Such manipulation leads to improper verification of cryptographic signature. The attack may be performed from remote. A high complexity level is associated with this attack. The exploitability is assessed as difficult. The exploit has been disclosed publicly and may be used. Upgrading to version 7.21 is capable of addressing this issue. It is advisable to upgrade the affected component. VulDB has contacted the vendor early and they confirmed quickly, that this issue got fixed already.
Affected Software
Remediation
Recommended actions to resolve this vulnerability, in priority order.
- Upgrade
Upgrade
Cesanta Mongooseto a version that resolves this vulnerability.Fixed in 7.21
Event History
Frequently Asked Questions
What is the severity of CVE-2026-6986?
The severity of CVE-2026-6986 is considered significant due to its impact on the GCM Authentication Tag Handler in Cesanta Mongoose.
How do I fix CVE-2026-6986?
To fix CVE-2026-6986, upgrade Cesanta Mongoose to version 7.21 or later.
What vulnerability does CVE-2026-6986 affect?
CVE-2026-6986 affects the function mg_aes_gcm_decrypt in the tls_aes128.c file of Cesanta Mongoose versions up to 7.20.
What components are affected by CVE-2026-6986?
CVE-2026-6986 specifically affects the GCM Authentication Tag Handler in Cesanta Mongoose.
Is CVE-2026-6986 exploitable?
Yes, CVE-2026-6986 can potentially allow attackers to bypass signature verification during decryption.