CVE-2026-6986
Cesanta Mongoose GCM Authentication Tag tls_aes128.c mg_aes_gcm_decrypt signature verification
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.
INFO
Published Date :
April 25, 2026, 5:16 p.m.
Last Modified :
April 25, 2026, 5:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-6986
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 2.0 | LOW | [email protected] | ||||
| CVSS 3.1 | LOW | [email protected] | ||||
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Upgrade Cesanta Mongoose to version 7.21.
- Update the GCM Authentication Tag Handler component.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-6986.
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-6986 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-6986
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-6986 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-6986 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Apr. 25, 2026
Action Type Old Value New Value Added 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. Added CVSS V4.0 AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CVSS V3.1 AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N Added CVSS V2 (AV:N/AC:H/Au:N/C:N/I:P/A:N) Added CWE CWE-345 Added CWE CWE-347 Added Reference https://github.com/cesanta/mongoose/releases/tag/7.21 Added Reference https://github.com/dwBruijn/CVEs/blob/main/Mongoose/AESGCM.md Added Reference https://vuldb.com/submit/796231 Added Reference https://vuldb.com/vuln/359529 Added Reference https://vuldb.com/vuln/359529/cti