CVE catalog
CVE-2026-6985
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
- Severity
- Medium · CVSS 5.5
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 - Published
- Source
- [NVD] · [CVE record]
- EPSS
- 0.56% · Oct 25, 2026
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.
Vulnerable and fixed packages
Distribution-reported package versions and fixes. These do not depend on matching against the OpenFactory package catalog.
| Distribution | Package | Release | Version | Status |
|---|---|---|---|---|
| Debian | swupdate | sid | 2026.05.1+git20261001+dfsg-2 | fixed |
| Debian | swupdate | forky | 2026.05.1+git20261001+dfsg-2 | fixed |
| Debian | swupdate | trixie | 2024.12.1+dfsg-3+deb13u2 | vulnerable |
| Debian | swupdate | bookworm | 2022.12+dfsg-4+deb12u2 | vulnerable |
| Debian | swupdate | bookworm-security | 2022.12+dfsg-4+deb12u3 | vulnerable |
| Cpe | swupdate | Not reported | Not reported | vulnerable |
| Cpe | mongoose | Not reported | 7.21 | fixed |
| Cpe | mongoose | Not reported | 7.21 | fixed |
Fixed-version evidence
| Distribution | Package | Type | Release | Fixed version | Urgency | Origin | Bugs |
|---|---|---|---|---|---|---|---|
| Debian | swupdate | source | sid | 2025.12+dfsg-10 | not yet assigned | Not reported | Not reported |
| Debian | swupdate | source | forky | 2025.12+dfsg-10 | not yet assigned | Not reported | Not reported |
| Debian | swupdate | source | trixie | (unfixed) | not yet assigned | Not reported | Not reported |
| Debian | swupdate | source | bookworm | (unfixed) | not yet assigned | Not reported | Not reported |
| Cpe | mongoose | cpe | Not reported | 7.21 | Not reported | Not reported | Not reported |
| Cpe | mongoose | cpe | Not reported | 7.21 | Not reported | NVD-CVE-2026-6985 | Not reported |
Notes
[trixie] swupdate: Minor issue [bookworm] swupdate: Minor issue
OpenFactory catalog packages
[Debian 12 (Bookworm)]
- [libswupdate0.1]Affected
Source package: [swupdate]
Details (4)
2022.12+dfsg-4+deb12u2· amd64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2022.12+dfsg-4+deb12u2· arm64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· amd64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· arm64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
- [libswupdate-dev]Affected
Source package: [swupdate]
Details (4)
2022.12+dfsg-4+deb12u2· amd64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2022.12+dfsg-4+deb12u2· arm64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· amd64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· arm64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
- [lua-swupdate]Affected
Source package: [swupdate]
Details (4)
2022.12+dfsg-4+deb12u2· amd64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2022.12+dfsg-4+deb12u2· arm64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· amd64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· arm64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
- [swupdate]Affected
Details (4)
2022.12+dfsg-4+deb12u2· amd64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2022.12+dfsg-4+deb12u2· arm64 · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· amd64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· arm64 · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
- [swupdate-doc]Affected
Source package: [swupdate]
Details (4)
2022.12+dfsg-4+deb12u2· all · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2022.12+dfsg-4+deb12u2· all · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· all · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· all · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
- [swupdate-www]Affected
Source package: [swupdate]
Details (4)
2022.12+dfsg-4+deb12u2· all · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2022.12+dfsg-4+deb12u2· all · bookwormAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· all · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
2024.12.1+dfsg-3~bpo12+1· all · bookworm-backportsAffected
nvd · swupdate · debian · bookworm; nvd · swupdate · debian · 12
[Debian 13 (Trixie)]
- [libswupdate0.1]Affected
Source package: [swupdate]
Details (4)
2024.12.1+dfsg-3+deb13u2· amd64 · trixieAffected
nvd · swupdate · debian · 13
2024.12.1+dfsg-3+deb13u2· arm64 · trixieAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· amd64 · trixie-backportsAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· arm64 · trixie-backportsAffected
nvd · swupdate · debian · 13
- [libswupdate-dev]Affected
Source package: [swupdate]
Details (4)
2024.12.1+dfsg-3+deb13u2· amd64 · trixieAffected
nvd · swupdate · debian · 13
2024.12.1+dfsg-3+deb13u2· arm64 · trixieAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· amd64 · trixie-backportsAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· arm64 · trixie-backportsAffected
nvd · swupdate · debian · 13
- [lua-swupdate]Affected
Source package: [swupdate]
Details (4)
2024.12.1+dfsg-3+deb13u2· amd64 · trixieAffected
nvd · swupdate · debian · 13
2024.12.1+dfsg-3+deb13u2· arm64 · trixieAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· amd64 · trixie-backportsAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· arm64 · trixie-backportsAffected
nvd · swupdate · debian · 13
- [swupdate]Affected
Details (4)
2024.12.1+dfsg-3+deb13u2· amd64 · trixieAffected
nvd · swupdate · debian · 13
2024.12.1+dfsg-3+deb13u2· arm64 · trixieAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· amd64 · trixie-backportsAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· arm64 · trixie-backportsAffected
nvd · swupdate · debian · 13
- [swupdate-doc]Affected
Source package: [swupdate]
Details (4)
2024.12.1+dfsg-3+deb13u2· all · trixieAffected
nvd · swupdate · debian · 13
2024.12.1+dfsg-3+deb13u2· all · trixieAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· all · trixie-backportsAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· all · trixie-backportsAffected
nvd · swupdate · debian · 13
- [swupdate-www]Affected
Source package: [swupdate]
Details (4)
2024.12.1+dfsg-3+deb13u2· all · trixieAffected
nvd · swupdate · debian · 13
2024.12.1+dfsg-3+deb13u2· all · trixieAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· all · trixie-backportsAffected
nvd · swupdate · debian · 13
2026.05.1+dfsg-1~bpo13+1· all · trixie-backportsAffected
nvd · swupdate · debian · 13
Observed:
References
- [https://github.com/cesanta/mongoose/releases/tag/7.21]
- [https://github.com/dwBruijn/CVEs/blob/main/Mongoose/TCP_opt_dos.md]
- [https://nvd.nist.gov/vuln/detail/CVE-2026-6985]
- [https://osv.dev/vulnerability/DEBIAN-CVE-2026-6985]
- [https://security-tracker.debian.org/tracker/CVE-2026-6985]
- [https://vuldb.com/submit/796230]
- [https://vuldb.com/vuln/359528]
- [https://vuldb.com/vuln/359528/cti]
[Debian Security Tracker] · [FIRST EPSS] · [National Vulnerability Database (NVD)] · [OSV Package Vulnerability Database]