Instituto Nacional de ciberseguridad. Sección Incibe
Instituto Nacional de Ciberseguridad. Sección INCIBE-CERT

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CVE-2026-6986

Severity CVSS v4.0:
MEDIUM
Type:
CWE-345 Insufficient Verification of Data Authenticity
Publication date:
25/04/2026
Last modified:
27/04/2026

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.

Impact

Vector 4.0
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 CVSS v4.0 Severity and Metrics:

Base Score: 6.30 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

Attack Vector (AV): Network
Attack Complexity (AC): High
Attack Requirements (AT): None
Privileges Required (PR): None
User Interaction (UI): None
Confidentiality (VC): None
Integrity (VI): Low
Availability (VA): None
Confidentiality (SC): None
Integrity (SI): None
Availability (SA): None
Exploit Maturity (E): POC

Base Score 4.0
6.30
Severity 4.0
MEDIUM
Vector 3.x
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N CVSS v3.1 Severity and Metrics:

Base Score: 3.70 LOW
Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Privileges Required (PR): None
User Interaction (UI): None
Scope (S): Unchanged
Confidentiality (C): None
Integrity (I): Low
Availability (A): None

Base Score 3.x
3.70
Severity 3.x
LOW
Vector 2.0
AV:N/AC:H/Au:N/C:N/I:P/A:N CVSS v2.0 Severity and Metrics:

Base Score: 2.60 LOW
Vector: AV:N/AC:H/Au:N/C:N/I:P/A:N

Attack Vector (AV): Network
Attack Complexity (AC): High
Authentication (Au): None
Confidentiality (C): None
Integrity (I): Physical
Availability (A): None

Base Score 2.0
2.60
Severity 2.0
LOW

References to Advisories, Solutions, and Tools