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Fencer Vulns
critical 9.8

CVE-2024-39844 json

In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.

published 2024-07-03 2 y ago modified 2026-06-17 4 mo ago also EUVD-2024-38265

cvss
9.8
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
3.9%
EPSS 3.9% chance of exploitation in 30 days, percentile 90%
public exploits
0
none known

Summary

In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.

Patch / fix

  • znc znc 1.9.1
  • znc Debian 12 1.8.2-3.1+deb12u1
  • znc Debian 14, Debian 13 1.9.1-1

debian advisories DEBIAN-CVE-2024-39844

  • znc Ubuntu 22.04 LTS 1.8.2-2ubuntu0.1
  • znc Ubuntu Pro 14.04 LTS 1.2-3ubuntu0.1+esm3
  • znc Ubuntu Pro 16.04 LTS 1.6.3-1ubuntu0.2+esm2
  • znc Ubuntu Pro 18.04 LTS 1.6.6-1ubuntu0.2+esm2
  • znc Ubuntu Pro 20.04 LTS 1.7.5-4ubuntu0.1~esm2
  • znc Ubuntu Pro 24.04 LTS 1.9.0-2ubuntu0.1~esm2

ubuntu advisories UBUNTU-CVE-2024-39844

Ubuntu security data © Canonical Ltd., from https://github.com/canonical/ubuntu-security-notices via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

  • znc Package Hub 15 SP6, openSUSE Leap 15.6 1.9.1-bp156.2.3.1
  • znc openSUSE Tumbleweed 1.9.1-1.1

opensuse advisories openSUSE-SU-2024:0203-1openSUSE-SU-2024:14115-1

  • znc Alpine 3.24, Alpine 3.23, Alpine 3.22 +2 more 1.9.1-r0

alpine advisories ALPINE-CVE-2024-39844

Alpine secdb © Alpine Linux, from https://secdb.alpinelinux.org via OSV; changed: normalised to fixed package versions per release. CC BY-SA 4.0

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2024-39844 updated

znc: remote code execution via modtcl

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
yes
Technical impact
total
Assessed
2 y ago

Exploit prediction

3.86% chance of exploitation in the next 30 days, higher than 90% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CISA ADP 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
CNA 3.1 9.8 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Affected products

  • znc znc

Classification

Weakness
  • CWE-94 Improper Control of Generation of Code

References

Sources

Fencer Vulns 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.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.