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Low · 3.7 CVE-2026-6986 EUVD-2026-25662GHSA-p5j9-fjff-qrmr

Cesanta Mongoose GCM Authentication Tag tls_aes128.c mg_aes_gcm_decrypt signature verification

Published Apr 25, 2026 · Updated Apr 27, 2026 · Assigned by VulDB

Description

A security vulnerability has been detected in Cesanta Mongoose up to 7.20. This issue affects the function mg_aes_gcm_decrypt of the file /src/tls_aes128.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 products

VendorProductAffectedFixed
Cesanta Mongoose 7.0, 7.1, 7.2, 7.3, 7.4, 7.5, 7.6, 7.7, 7.8, 7.9, 7.10, 7.11, 7.12, 7.13, 7.14, 7.15, 7.16, 7.17, 7.18, 7.19, 7.20 7.21

Fixed in Linux distributions

Distributions backport fixes, so the version that fixes this vulnerability differs per release — upgrade to at least the version shown. From the distributions' security trackers and advisories.

ReleasePackageFixed inAdvisory
Debian 14 swupdate 2025.12+dfsg-10 —
Debian 13 swupdate No fix yet —
Debian 12 swupdate No fix yet —
ReleasePackageFixed inAdvisory
Ubuntu 26.10 swupdate No fix yet —
Ubuntu 26.04 LTS swupdate No fix yet —
Ubuntu 25.10 swupdate No fix yet —
Ubuntu 24.04 LTS swupdate No fix yet —
Ubuntu 22.04 LTS swupdate No fix yet —

References