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Fencer Intel
high 8.8

CVE-2026-129123 json

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

published yesterday modified yesterday also EUVD-2026-125556

cvss
8.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.6%
EPSS 0.6% chance of exploitation in 30 days, percentile 49%
public exploits
0
none known

Summary

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.

Patch / fix

  • OpenKermit C-Kermit 11.1.515
  • ckermit Debian 14 1:11.1.515-1

debian advisories DEBIAN-CVE-2026-129123

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CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
yesterday

Exploit prediction

0.60% chance of exploitation in the next 30 days, higher than 49% of all scored CVEs (FIRST EPSS, 2026-11-14).

Exploits and checks

  • github.com https://github.com/OpenKermit/ckermit/security/advisories/GHSA-c5px-7h4c-gj8p referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.7 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 3.1 8.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CNA 4.0 8.7 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

Affected products

  • OpenKermit C-Kermit

Classification

Weakness
  • CWE-120 Buffer Copy without Checking Size of Input

References

Sources

Fencer Intel keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.