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CVE-2026-6986

Cesanta Mongoose GCM Authentication Tag tls_aes128.c mg_aes_gcm_decrypt signature verification

Published: Apr 25, 2026Updated: Apr 29, 2026 Sources: CVE List NVDCWE-345
NVD MITRE
3.7CVSSLOW
EPSS Score
0.2%
Top 88.1%
CISA KEV
Not in KEV
Exploits
No Known Exploits
Remediation
No Fix Available

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.

CVSS Vector Breakdown

AV:NAC:HPR:NUI:NS:UC:NI:LA:N
Exploitability
AV:NAttack Vector
Network
AC:HAttack Complexity
High
PR:NPrivileges Required
None
UI:NUser Interaction
None
Scope
S:UScope
Unchanged
Impact
C:NConfidentiality
None
I:LIntegrity
Low
A:NAvailability
None
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Weaknesses

CWE-345CWE-347

Affected Products

mongoosecesantaOSS Libraries
MongooseCesantaOSS Libraries
cesantaoss-projectOSS Libraries

Attack Graph

Products CVE Techniques Tactics

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Exploitability

No known exploits, KEV entries, or remediation guidance available for this vulnerability yet.

MITRE ATT&CK

1 technique
Collection
View detailed technique mapping

References

https://github.com/cesanta/mongoose/releases/tag/7.21
github.com
https://github.com/dwBruijn/CVEs/blob/main/Mongoose/AESGCM.md
github.com
https://vuldb.com/submit/796231
vuldb.com
and 2 more references View all →

Timeline

Published
Apr 25, 2026
Last Updated
Apr 29, 2026

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