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Vulnerability · Published Feb 23, 2026 · Assigned by VulDB

CVE-2026-2968Cesanta Mongoose Poly1305 Authentication Tag tls_chacha20.c mg_chacha20_poly1305_decrypt signature verification

Low 3.7

In plain English

A low-severity insufficient verification of data authenticity in Mongoose from Cesanta. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.3% (higher than 17% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.7Low
Exploit odds (30 days)0.3%top 83.0% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

A vulnerability was detected in Cesanta Mongoose up to 7.20. This impacts the function mg_chacha20_poly1305_decrypt of the file /src/tls_chacha20.c of the component Poly1305 Authentication Tag Handler. The manipulation results in improper verification of cryptographic signature. The attack may be launched remotely. This attack is characterized by high complexity. The exploitability is said to be difficult. The exploit is now public and may be used. The vendor was contacted early about this disclosure but did not respond in any way.

Affected packages & fixed versions

EcosystemPackageFixed inAdvisory
Debian:12swupdateno fix listedDEBIAN-CVE-2026-2968
Debian:13swupdateno fix listedDEBIAN-CVE-2026-2968
Debian:14swupdate2025.12+dfsg-10DEBIAN-CVE-2026-2968
Ubuntu:22.04:LTSswupdateno fix listedUBUNTU-CVE-2026-2968
Ubuntu:24.04:LTSswupdateno fix listedUBUNTU-CVE-2026-2968
Ubuntu:25.10swupdateno fix listedUBUNTU-CVE-2026-2968
Ubuntu:26.04:LTSswupdateno fix listedUBUNTU-CVE-2026-2968
Ubuntu:26.10swupdateno fix listedUBUNTU-CVE-2026-2968

Affected products (as reported)

VendorProductVersions
Cesanta Mongoose 7.07.17.27.37.47.57.67.7

Weakness: CWE-347, CWE-345 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:L/A:N/E:P/RL:X/RC:R

References