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CVE-2026-129126

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

  • Critical 9.2

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.

Key facts

Published
13 Nov 2026
Last changed
13 Nov 2026
Assigned by
VulnCheck
EPSS
0.604% likely to be exploited in the next 30 days, higher than 49.482% of CVEs (scores for 15 Nov 2026)

Severity scores

Each score is shown as its source gave it. They are not averaged or merged.

  • 9.2CVSS 4.0, Criticalfrom the CNA (VulnCheck)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
  • 8.1CVSS 3.1, Highfrom the CNA (VulnCheck)CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H

Historical context and remediation

This reference retains the original CVE publication date. A recent record update does not mean a new attack occurred.

No separately sourced impact summary is available on this page yet. Consult the description, version data and dated exploitation evidence.

No explicit remediation statement is available on this page yet. Consult the original record and vendor references before choosing a fix.

Version statuses below come from the CNA. An “unaffected” version is not necessarily a currently supported release or proof of a patch date. EPSS is a dated risk estimate, not a count of historical attacks.

Read the original CVE record.

Affected products

VendorProductVersions
OpenKermitC-Kermit
  • Default status: unaffected
  • 0 up to but excluding 11.1.515 (affected)

Timeline

  1. 13 Nov 2026 Published

Weakness

References