CVE-2026-2967
Cesanta Mongoose TCP Sequence Number net_builtin.c getpeer verification of source
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.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- High
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- None
- Integrity
- None
- Availability
- Low
Exploit likelihood
What each source reports
CVE List Score used
6.3
Cesanta Mongoose TCP Sequence Number net_builtin.c getpeer verification of source
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.
- Record
CVE-2026-2967- CVSS 4.0
- 6.3 Medium
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 - CVSS 3.1
- 3.7 Low
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 - CVSS 3.0
- 3.7 Low
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 - CVSS 2.0
- 2.6
AV:N/AC:H/Au:N/C:N/I:N/A:P/E:POC/RL:ND/RC:UR - Weakness
- CWE-940
- Updated
- 2026-11-02
EUVDEUVD-2026-7603
6.3
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.
- Record
EUVD-2026-7603- CVSS 4.0
- 6.3 Medium
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 - Updated
- 2026-11-02
GitHub AdvisoriesGHSA-c6h3-vh8h-r8mj
2.9
A security vulnerability has been detected in Cesanta Mongoose up to 7.20. This affects the...
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.
- Record
GHSA-c6h3-vh8h-r8mj- CVSS 4.0
- 2.9 Low
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 - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Weakness
- CWE-940
- Updated
- 2026-11-02
NVD
2.9
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.
- Record
CVE-2026-2967- CVSS 4.0
- 2.9 Low
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 - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - CVSS 2.0
- 2.6 Low
AV:N/AC:H/Au:N/C:N/I:N/A:P - Weakness
- CWE-940
- Updated
- 2026-11-02
OSV
2.9
Cesanta Mongoose TCP Sequence Number net_builtin.c getpeer verification of source
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.
- Record
CVE-2026-2967- CVSS 4.0
- 2.9 Low
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 - Weakness
- CWE-940
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-2967
2.9
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.
- Record
DEBIAN-CVE-2026-2967- CVSS 4.0
- 2.9 Low
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 - Updated
- 2026-11-02
OSVJLSEC-2026-367
2.9
A security vulnerability has been detected in Cesanta Mongoose up to 7.20
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.
- Record
JLSEC-2026-367- CVSS 4.0
- 2.9 Low
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 - CVSS 2.0
- 2.6 Low
AV:N/AC:H/Au:N/C:N/I:N/A:P - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-2967
2.9
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.
- Record
UBUNTU-CVE-2026-2967- CVSS 4.0
- 2.9 Low
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 - CVSS 3.1
- 3.7 Low
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:L - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
swupdateDebian:12 |
All versions, plus listed versions 2022.12+dfsg-42022.12+dfsg-4+deb12u12022.12+dfsg-4+deb12u1~bpo11+12022.12+dfsg-4+deb12u22023.05+dfsg-1 Show 45 moreShow less2023.05+dfsg-22023.05+dfsg-2~bpo12+12023.05+dfsg-32023.05+dfsg-42023.05+dfsg-52023.05+dfsg-5~bpo12+12023.12+dfsg-12023.12+dfsg-1~bpo12+12023.12.1+dfsg-12023.12.1+dfsg-1~bpo12+12023.12.1+dfsg-22023.12.1+dfsg-2~bpo12+12024.05+dfsg-12024.05.2+dfsg-12024.05.2+dfsg-22024.05.2+dfsg-2~bpo12+12024.12+dfsg-12024.12+dfsg-22024.12+dfsg-2~bpo12+12024.12.1+dfsg-12024.12.1+dfsg-1~bpo12+12024.12.1+dfsg-22024.12.1+dfsg-32024.12.1+dfsg-3~bpo12+12025.05+dfsg-12025.05+dfsg-22025.05+dfsg-2~bpo13+12025.05+dfsg-32025.05+dfsg-3~bpo13+12025.12+dfsg-12025.12+dfsg-102025.12+dfsg-10~bpo13+12025.12+dfsg-10~bpo13+22025.12+dfsg-22025.12+dfsg-2~bpo13+12025.12+dfsg-32025.12+dfsg-42025.12+dfsg-52025.12+dfsg-62025.12+dfsg-72025.12+dfsg-7~bpo13+12025.12+dfsg-82025.12+dfsg-92026.05+dfsg-12026.05+dfsg-2 |
None known |
swupdateDebian:13 |
All versions, plus listed versions 2024.12.1+dfsg-32024.12.1+dfsg-3+deb13u12024.12.1+dfsg-3+deb13u22025.05+dfsg-12025.05+dfsg-2 Show 24 moreShow less2025.05+dfsg-2~bpo13+12025.05+dfsg-32025.05+dfsg-3~bpo13+12025.12+dfsg-12025.12+dfsg-102025.12+dfsg-10~bpo13+12025.12+dfsg-10~bpo13+22025.12+dfsg-22025.12+dfsg-2~bpo13+12025.12+dfsg-32025.12+dfsg-42025.12+dfsg-52025.12+dfsg-62025.12+dfsg-72025.12+dfsg-7~bpo13+12025.12+dfsg-82025.12+dfsg-92026.05+dfsg-12026.05+dfsg-22026.05+dfsg-32026.05+dfsg-3~bpo13+12026.05+dfsg-42026.05.1+dfsg-12026.05.1+dfsg-1~bpo13+1 |
None known |
swupdateDebian:14 |
before 2025.12+dfsg-10, plus listed versions 2024.12.1+dfsg-32025.05+dfsg-12025.05+dfsg-22025.05+dfsg-2~bpo13+12025.05+dfsg-3 Show 14 moreShow less2025.05+dfsg-3~bpo13+12025.12+dfsg-12025.12+dfsg-10~bpo13+12025.12+dfsg-10~bpo13+22025.12+dfsg-22025.12+dfsg-2~bpo13+12025.12+dfsg-32025.12+dfsg-42025.12+dfsg-52025.12+dfsg-62025.12+dfsg-72025.12+dfsg-7~bpo13+12025.12+dfsg-82025.12+dfsg-9 |
2025.12+dfsg-10 |
Mongoose_jllJulia |
before 7.21.0+0 | 7.21.0+0 |
opencpnUbuntu:20.04:LTS |
All versions, plus listed versions 5.0.0+dfsg-1 |
None known |
opencpnUbuntu:22.04:LTS |
All versions, plus listed versions 5.2.4+dfsg-15.6.0+dfsg1-1 |
None known |
opencpnUbuntu:24.04:LTS |
All versions, plus listed versions 5.8.4+dfsg-15.8.4+dfsg-1build35.8.4+dfsg-1build4 |
None known |
opencpnUbuntu:25.10 |
All versions, plus listed versions 1:5.10.2+dfsg-1 |
None known |
opencpnUbuntu:26.10 |
All versions, plus listed versions 1:5.12.4+dfsg-11:5.14.1+dfsg-31:5.14.1+dfsg-4 |
None known |
opencpnUbuntu:26.04:LTS |
All versions, plus listed versions 1:5.10.2+dfsg-11:5.12.4+dfsg-1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, GitHub Advisories, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-2967 is a medium vulnerability (CVSS 6.3) in Automattic Mongoose, published February 23, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.57%, the 47th percentile. Fixed in swupdate 2025.12+dfsg-10.
References
Left out here: 5 versions. The JSON record has them.