C-Kermit before 11.1.515 contains a heap buffer overflow vulnerability in putsrv() in ckcfns.c that allows malicious
Source GCVE Database
Not known to be exploited · CVSS 9.2 Critical : upgrade to 11.1.515 as a priority.
Data as of 13 Nov 2026, 20:01 UTC
Thin evidence
One scorer or none| CNA (VulnCheck) | CVSS 4.0 | 9.2 |
|---|---|---|
| CNA (VulnCheck) | CVSS 3.1 | 8.1 |
- Patch
- Available – fixed in 11.1.515
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:NExploitation evidence
Disclosed: evidence found.
CVE published 13 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 13 Nov 2026.
What to do
Upgrade C-Kermit to 11.1.515.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| OpenKermitC-Kermit | Affected
| Fixed in
|
GitHubC-Kermitpkg:github/C-KermitOther threats | Affected
| Fixed in
|
Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.
AI-suggested
Upgrade to C-Kermit version 11.1.515 or later where this heap buffer overflow vulnerability is fixed. Until patched, avoid accepting untrusted packets or disable vulnerable features if possible.
Description
C-Kermit versions prior to 11.1.515 contain a heap buffer overflow vulnerability in the putsrv() function within ckcfns.c. This flaw allows malicious peers to write beyond the srvcmd buffer by sending specially crafted packets using Kermit repeat-count compression in server command, GET, or file-header packets. The vulnerability can lead to arbitrary code execution or denial of service on affected servers or receiving instances.
References
- github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p (opens in a new tab)
- nvd.nist.gov/vuln/detail/CVE-2026-129126 (opens in a new tab)
- github.com/OpenKermit/ckermit/commit/37e54720779237897bc6887efac42fe138817897 (opens in a new tab)
- github.com/OpenKermit/ckermit/blob/v11.0.514/ckcfns.c (opens in a new tab)
- github.com/OpenKermit/ckermit/releases/tag/v11.1.515 (opens in a new tab)
- vulncheck.com/advisories/c-kermit-before-11.1.515-heap-buffer-overflow-via-putsrv-packet-decoding (opens in a new tab)