by Kastro
Paper/Archive/CVE-2026-129126

CVE-2026-129126

OpenKermit C-Kermit — C-Kermit before 11.1.515 Heap Buffer Overflow via putsrv() Packet Decoding

CVSS 9.2
critical.is priorityof 100
28
CVSS 9.2 (CNA)9.2 / 10 × 3027.6Not in CISA KEV+300.0No EPSS score.000 × 200.0No public exploit+100.0SSVC exploitation: unknown+100.0
Description · from the CVE record

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.

Affected

ProductAffectedFixed inSource
C-Kermit< 11.1.51511.1.515CNA

Scores by source

VulnCheck (CNA)9.2CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N
VulnCheck (CNA)8.1CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

References

advisorygithub.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8ppatchgithub.com/OpenKermit/ckermit/commit/37e54720779237897bc6887efac42fe138817897refgithub.com/OpenKermit/ckermit/releases/tag/v11.1.515writeupgithub.com/OpenKermit/ckermit/blob/v11.0.514/ckcfns.c#L461writeupvulncheck.com/advisories/c-kermit-before-11.1.515-heap-buffer-overflow-via-putsrv-packet-decoding