CVE-2026-129126

critical

Description

C-Kermit before 11.1.515 contains a heap buffer overflow vulnerability in putsrv() in ckcfns.c that allows malicious peers to write past the srvcmd buffer by sending crafted packets. Attackers can use Kermit repeat-count compression in server command, GET, or file-header packets to write attacker-chosen bytes beyond the heap buffer on servers or receiving instances.

References

https://www.vulncheck.com/advisories/c-kermit-before-11.1.515-heap-buffer-overflow-via-putsrv-packet-decoding

https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p

https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515

https://github.com/OpenKermit/ckermit/commit/37e54720779237897bc6887efac42fe138817897

https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcfns.c#L461

https://euvd.enisa.europa.eu/vulnerability/EUVD-2026-125553

Details

Source: Mitre, NVD

Published: 2026-11-13

Updated: 2026-11-13

Risk Information

CVSS v2

Base Score: 7.6

Vector: CVSS2#AV:N/AC:H/Au:N/C:C/I:C/A:C

Severity: High

CVSS v3

Base Score: 8.1

Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Severity: High

CVSS v4

Base Score: 9.2

Vector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N

Severity: Critical

EPSS

EPSS: 0.00604