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Public proof of concept

CVE-2026-129123

C-Kermit 8.0.200 before 11.1.515 FTP Client Buffer Overflow via PBSZ and ADAT Replies

A public proof of concept exists; no exploitation attested.

  • Published2026-11-13
  • WeaknessCWE-120

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

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.

Timeline

dates in UTC
  1. 2026-11-1316:23CVE publishedCNA

Versions per branch

Products declared by the CNA

As VulnCheck, the CNA that assigned this CVE, declared them in the CVE record; versions as written. NVD lists no product for this CVE yet: this is the only product data so far.

  • OpenKermit C-Kermitother versions: not affected
    Affected
    • ≥ 8.0.200, < 11.1.515fixed in 11.1.515semver

Source: the CNA record (CVE Program), © The MITRE Corporation,CVE Terms of UseCVE recordupdated 2026-11-13

Neither OSV.dev nor the vendor advisories we read list affected versions for CVE-2026-129123 yet.

Full record on NVD

Fix

No fix published by the sources we read yet. NVD record

Detection

Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof of concept
Metasploit modules
none listed
Metasploit Framework

Sources

  • CISA-ADPSSVC decisionpoc2026-11-13
  • CNACVSS 4.08.72026-11-13
  • CNACVSS 3.18.82026-11-13
  • NVDCVSS 3.18.8read 2026-11-13
  • CNAweakness (CWE)CWE-1202026-11-13
  • NVDweakness (CWE)CWE-120read 2026-11-13
  • GitHub Advisoriesadvisory—

Identifiers

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 4.0 vector
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
Published
2026-11-13
Last Modified
2026-11-13
NVD status
Deferred
GitHub Advisory
GHSA-f8jp-whmp-v2jf

Frequently asked questions

What is CVE-2026-129123?

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.

Is CVE-2026-129123 actively exploited?

A proof-of-concept exploit exists for CVE-2026-129123, but active exploitation has not been confirmed at this time.

What is the CVSS score for CVE-2026-129123?

CVE-2026-129123 has a CVSS v3 base score of 8.8 (HIGH severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H.

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