CVE-2026-129123
C-Kermit 8.0.200 before 11.1.515 FTP Client Buffer Overflow via PBSZ and ADAT Replies
C-Kermit 8.0.200 before 11.1.515 contains a buffer overflow vulnerability in getreply() in ckcftp.c that allows malicious FTP servers to overwrite client memory by sending overlong security replies. Attackers controlling or intercepting an FTP server can send long PBSZ replies after AUTH TLS, or long ADAT replies in GSSAPI, Kerberos 4, and SRP builds, overflowing the static reply_buf with attacker-controlled bytes.
Fixes and workarounds
Fix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckFix
The reporting source identifies this reference as a patch. Check the advisory for affected versions and supported release branches.
Source: CNA: VulnCheckAffected products and versions
| Product | Versions | Authority |
|---|---|---|
| C-Kermit OpenKermit OpenKermit/ckermit
github |
≥ 8.0.200; < 11.1.515 (affected, semver)
Other versions: unaffected |
CNA: VulnCheck |
Version ranges are source assertions. Check the vendor advisory and your installed configuration before determining exposure.
CVSS assessments
| Version / score | Vector | Authority |
|---|---|---|
| 4.0 / 8.7 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N | CNA: VulnCheck |
| 3.1 / 8.8 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | CNA: VulnCheck |
| 4.0 / 8.7 high |
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X | NVD: [email protected] |
| 3.1 / 8.8 high |
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H | NVD: [email protected] |
Exploit evidence
- https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p
exploit · ADP: CISA-ADP
References
- https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8pCNA: VulnCheck · vendor-advisory
- https://github.com/OpenKermit/ckermit/commit/39ab009a365b97632e9975e1266fa618c4bdc59fCNA: VulnCheck · patch
- https://github.com/OpenKermit/ckermit/commit/bec28a4d544031fa07a07aacba3df5dd1202ef69CNA: VulnCheck · patch
- https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515CNA: VulnCheck · release-notes
- https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcftp.c#L11161CNA: VulnCheck · technical-description
- https://www.vulncheck.com/advisories/c-kermit-8.0.200-before-11.1.515-ftp-client-buffer-overflow-via-pbsz-and-adat-repliesCNA: VulnCheck · third-party-advisory
- https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8pADP: CISA-ADP · exploit
- https://github.com/OpenKermit/ckermit/blob/v11.0.514/ckcftp.c#L11161[email protected]
- https://github.com/OpenKermit/ckermit/commit/39ab009a365b97632e9975e1266fa618c4bdc59f[email protected]
- https://github.com/OpenKermit/ckermit/commit/bec28a4d544031fa07a07aacba3df5dd1202ef69[email protected]
- https://github.com/OpenKermit/ckermit/releases/tag/v11.1.515[email protected]
- https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p[email protected]
- https://www.vulncheck.com/advisories/c-kermit-8.0.200-before-11.1.515-ftp-client-buffer-overflow-via-pbsz-and-adat-replies[email protected]
For agents and automation
Read public disclosures for free as Markdown or JSON. Compatible browsers also expose native WebMCP tools to search disclosures, read this page, and discover API access.
Use the ontology-linked Cyber API with x402 pay per request, or a Y2 Pro or Elite API key with the intel:cyber scope.
Endpoints and access details
https://api.y2.dev/api/v2/cyber/cveshttps://api.y2.dev/api/v2/cyber/cves/{cveId}
A workspace owner or admin can create a Pro or Elite API key. Send Authorization: Bearer <Y2_API_KEY> from your trusted agent runtime.
For x402, omit Authorization and read the HTTP 402 payment challenge before signing a retry. Public browser tools do not make payments.