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
| Vendor | Product | Affected | Fixed |
|---|---|---|---|
| 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.
Debian
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| Debian 14 | swupdate | 2025.12+dfsg-10 | — |
| Debian 13 | swupdate | No fix yet | — |
| Debian 12 | swupdate | No fix yet | — |
Ubuntu
Security tracker ↗| Release | Package | Fixed in | Advisory |
|---|---|---|---|
| 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
- VDB-359529 | Cesanta Mongoose GCM Authentication Tag tls_aes128.c mg_aes_gcm_decrypt signature verification vdb-entry technical-description
- VDB-359529 | CTI Indicators (IOB, IOC, IOA) signature permissions-required
- Submit #796231 | Cesanta Mongoose 7.20 Improper Verification of Cryptographic Signature third-party-advisory
- https://github.com/dwBruijn/CVEs/blob/main/Mongoose/AESGCM.md exploit
- https://github.com/cesanta/mongoose/releases/tag/7.21 patch