Improper Verification of Cryptographic Signature Affecting cesanta/mongoose package, versions [,7.21)
Threat Intelligence
Snyk has a proof-of-concept or detailed explanation of how to exploit this vulnerability.
The probability is the direct output of the EPSS model, and conveys an overall sense of the threat of exploitation in the wild. The percentile measures the EPSS probability relative to all known EPSS scores. Note: This data is updated daily, relying on the latest available EPSS model version. Check out the EPSS documentation for more details.
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Test your applications- Snyk IDSNYK-UNMANAGED-CESANTAMONGOOSE-16300214
- published27 Apr 2026
- disclosed25 Apr 2026
- creditdwBruijn
Introduced: 25 Apr 2026
CVE-2026-6986 (opens in a new tab)How to fix?
Upgrade cesanta/mongoose to version 7.21 or higher.
Overview
cesanta/mongoose is a networking library for C/C++. It implements event-driven non-blocking APIs for TCP, UDP, HTTP, WebSocket, MQTT.
Affected versions of this package are vulnerable to Improper Verification of Cryptographic Signature in the mg_aes_gcm_decrypt function of the GCM Authentication Tag Handler. An attacker can bypass cryptographic signature verification by sending specially crafted data to the affected process.