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UK Cyber Defence
VulnerabilityAnalyzed

CVE-2026-6985

A weakness has been identified in Cesanta Mongoose up to 7.20.

MEDIUM 5.5EPSS 0.56%

Does this matter?

Lower severity and a low EPSS score (0.56%). Track it; it rarely justifies an emergency change on its own.

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.

CVSS 4.0
5.5 MEDIUMCVSS: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/M
EPSS
0.56% probability · 45th percentile
CISA KEV
Not listed
Weakness
CWE-404, CWE-835
Affected
cesanta/mongoose
Source
cna@vuldb.com

References

Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.