CVE-2026-6985
Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop
- Published
- Updated
- Reserved
- Assigned by
- VulDB
Description
A weakness has been identified in Cesanta Mongoose up to 7.20. This vulnerability affects the function handle_opt of the file /src/net_builtin.c of the component TCP Option Handler. This manipulation of the argument optlen causes infinite loop. The attack is possible to be carried out remotely. The exploit has been made available to the public and could be used for attacks. Upgrading to version 7.21 is able to resolve this issue. Upgrading the affected component is advised. VulDB has contacted the vendor early and they confirmed quickly, that this issue got fixed already.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| VulDBCNA (assigner) | 4.0 | Medium6.9 | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:L/SC:N/SI:N/SA:N/E:P |
| VulDBCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C |
| VulDBCNA (assigner) | 3.0 | Medium5.3 | CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L/E:P/RL:O/RC:C |
| VulDBCNA (assigner) | 2.0 | Medium5.0 | AV:N/AC:L/Au:N/C:N/I:N/A:P/E:POC/RL:OF/RC:C |
| NVDNVD · Analyzed | 4.0 | Medium5.5 | CVSS:4.0/AV:N/AC:L/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)
- 0.56% · top 53% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: poc · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.9.
Weakness
Affected products
References (5)
- VDB-359528 | Cesanta Mongoose TCP Option net_builtin.c handle_opt infinite loop (opens in a new tab)vdb-entrytechnical-description
- VDB-359528 | CTI Indicators (IOB, IOC, TTP, IOA) (opens in a new tab)signaturepermissions-required
- Submit #796230 | Cesanta Mongoose 7.20 Denial of Service (opens in a new tab)third-party-advisory
- https://github.com/dwBruijn/CVEs/blob/main/Mongoose/TCP_opt_dos.md (opens in a new tab)exploit
- https://github.com/cesanta/mongoose/releases/tag/7.21 (opens in a new tab)patch
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)
- 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://trackcve.app/cve/CVE-2026-6985)Record last updated .