CVE-2026-2967Cesanta Mongoose TCP Sequence Number net_builtin.c getpeer verification of source
- 6.3MediumCVSS base score
- 0.57%Exploitation in 30 daysEPSS · top 52% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- YesPublic exploitsa reference or SSVC says so
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.
Public exploit
An exploit or proof of concept is public: anyone can try it against an unpatched system. A reference of the record is tagged as an exploit. CISA's SSVC rates its exploitation: a proof of concept is public.
Show the exploits1
References tagged exploit1 reference
Timeline
ID reserved
By VulDB
- 1 day later
· 1 day later
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulDBCNA (assigner) | 4.0 | Medium6.3 | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P |
| VulDBCNA (assigner) | 3.1 | Low3.7 | 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 |
| VulDBCNA (assigner) | 3.0 | Low3.7 | CVSS:3.0/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:X/RC:R |
| VulDBCNA (assigner) | 2.0 | Low2.6 | AV:N/AC:H/Au:N/C:N/I:N/A:P/E:POC/RL:ND/RC:UR |
| NVDNVD · Analyzed | 4.0 | Low2.9 | CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.57% · top 52% of all CVEs (13 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.3.
Affected products
References
References5
- VDB-347334 | Cesanta Mongoose TCP Sequence Number net_builtin.c getpeer verification of source (opens in a new tab)vdb-entrytechnical-description
- VDB-347334 | CTI Indicators (IOB, IOC, IOA) (opens in a new tab)signaturepermissions-required
- Submit #755450 | Cesanta Mongoose Embedded Web Server 7.20 Improper Validation of Specified Index, Position, or Offset in I (opens in a new tab)third-party-advisory
- https://github.com/dwBruijn/CVEs/blob/main/Mongoose/tcp_rst.md (opens in a new tab)related
- https://github.com/dwBruijn/CVEs/blob/main/Mongoose/tcp_rst.md#poc (opens in a new tab)exploit
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-7603 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-2967)Record last updated .