CVE-2026-6986CWE-345CWE-347

Cesanta Mongoose GCM Authentication Tag tls_aes128.c mg_aes_gcm_decrypt signature verification

Medium · published April 25, 2026

CVSS v4.0
6.3
EPSS
0%
Percentile
15.9
In the wild
Unconfirmed
What it is

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.

The record
Technical detail
CVSS v4.0
6.3 · MEDIUM
Vector
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P
EPSS
0.00253 · 15.9th percentile
Weaknesses
CWE-345 · Insufficient Verification of Data Authenticity; CWE-347 · Improper Verification of Cryptographic Signature
Published
2026-04-25T16:30Z
EPSS history
Timeline
  • 25 APR 16:30Z
    Cesanta Mongoose GCM Authentication Tag tls_aes128.c mg_aes_gcm_decrypt signature verification
    cvelistv5