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Vulnerability · Published Feb 23, 2026 · Assigned by VulDB

CVE-2026-2967Cesanta Mongoose TCP Sequence Number net_builtin.c getpeer verification of source

Low 3.7

In plain English

A low-severity security flaw in Mongoose from Cesanta. Proof-of-concept exploit code is public. The chance it is exploited in the next 30 days is estimated at 0.6% (higher than 48% of all known vulnerabilities). Fixed versions are available - upgrade the affected package.

Severity (CVSS 3.1)3.7Low
Exploit odds (30 days)0.6%top 52.4% of all CVEs
Exploited in the wildNo reportsCISA SSVC: poc
Attack toolingNoneno public tooling known

Official description

A security vulnerability has been detected in Cesanta Mongoose up to 7.20. This affects the function getpeer of the file /src/net_builtin.c of the component TCP Sequence Number Handler. The manipulation leads to improper verification of source of a communication channel. The attack may be initiated remotely. The attack's complexity is rated as high. The exploitability is reported as difficult. The exploit has been disclosed publicly 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-2026-2967
Debian:13swupdateno fix listedDEBIAN-CVE-2026-2967
Debian:14swupdate2025.12+dfsg-10DEBIAN-CVE-2026-2967
Ubuntu:22.04:LTSopencpnno fix listedUBUNTU-CVE-2026-2967
Ubuntu:24.04:LTSopencpnno fix listedUBUNTU-CVE-2026-2967
Ubuntu:25.10opencpnno fix listedUBUNTU-CVE-2026-2967
Ubuntu:26.04:LTSopencpnno fix listedUBUNTU-CVE-2026-2967
Ubuntu:26.10opencpnno fix listedUBUNTU-CVE-2026-2967

Affected products (as reported)

VendorProductVersions
Cesanta Mongoose 7.07.17.27.37.47.57.67.7

Weakness: CWE-940 · Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R

References