CVE-2024-39844
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- None
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Exploit likelihood
What each source reports
CVE List Score used
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
CVE-2024-39844- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
EUVDEUVD-2024-38265
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
EUVD-2024-38265- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
GitHub AdvisoriesGHSA-qh94-pjxq-88v7
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
GHSA-qh94-pjxq-88v7- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
NVD
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
CVE-2024-39844- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Weakness
- CWE-94
- Updated
- 2026-11-02
OSVALPINE-CVE-2024-39844
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
ALPINE-CVE-2024-39844- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-03
OSV
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
CVE-2024-39844- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
Show 6 moreShow less
OSVDEBIAN-CVE-2024-39844
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
DEBIAN-CVE-2024-39844- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVUBUNTU-CVE-2024-39844
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK.
- Record
UBUNTU-CVE-2024-39844- CVSS 3.1
- 9.8 Critical
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H - Updated
- 2026-11-02
OSVMGASA-2024-0257 No score
Updated znc packages fix security vulnerability
In ZNC before 1.9.1, remote code execution can occur in modtcl via a KICK. (CVE-2024-39844)
- Record
MGASA-2024-0257- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:0203-1 No score
Security update for znc
This update for znc fixes the following issues:
Update to 1.9.1 (boo#1227393, CVE-2024-39844)
- This is a security release to fix CVE-2024-39844: remote code execution vulnerability in modtcl. To mitigate this for existing installations, simply unload the modtcl module for every user, if it's loaded. Note that only users with admin rights can load modtcl at all.
- Improve tooltips in webadmin.
- Record
openSUSE-SU-2024:0203-1- Updated
- 2026-11-02
OSVopenSUSE-SU-2024:14115-1 No score
znc-1.9.1-1.1 on GA media
These are all security issues fixed in the znc-1.9.1-1.1 package on the GA media of openSUSE Tumbleweed.
- Record
openSUSE-SU-2024:14115-1- Updated
- 2026-11-02
OSVUSN-6990-1 No score
znc vulnerability
Johannes Kuhn (DasBrain) discovered that znc incorrectly handled user input under certain operations. An attacker could possibly use this issue to execute arbitrary code on a user's system if the user was tricked into joining a malicious server.
- Record
USN-6990-1- Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
zncAlpine:v3.20 |
before 1.9.1-r0 | 1.9.1-r0 |
zncAlpine:v3.21 |
before 1.9.1-r0 | 1.9.1-r0 |
zncAlpine:v3.22 |
before 1.9.1-r0 | 1.9.1-r0 |
zncAlpine:v3.23 |
before 1.9.1-r0 | 1.9.1-r0 |
zncAlpine:v3.24 |
before 1.9.1-r0 | 1.9.1-r0 |
zncDebian:12 |
before 1.8.2-3.1+deb12u1, plus listed versions 1.8.2-3.1 |
1.8.2-3.1+deb12u1 |
zncDebian:13 |
before 1.9.1-1 | 1.9.1-1 |
zncDebian:14 |
before 1.9.1-1 | 1.9.1-1 |
zncDebian:11 |
before 1.8.2-2+deb11u1, plus listed versions 1.8.2-2 |
1.8.2-2+deb11u1 |
zncMageia:9 |
before 1.8.2-21.1.mga9 | 1.8.2-21.1.mga9 |
Show 9 moreShow less
| Package | Affected | Fixed |
|---|---|---|
zncUbuntu:Pro:14.04:LTS |
before 1.2-3ubuntu0.1+esm3, plus listed versions 1.0-51.0-5build11.2-11.2-21.2-31.2-3build11.2-3ubuntu0.11.2-3ubuntu0.1+esm1 |
1.2-3ubuntu0.1+esm3 |
zncUbuntu:Pro:16.04:LTS |
before 1.6.3-1ubuntu0.2+esm2, plus listed versions 1.6.1-11.6.1-1build11.6.1-21.6.2-11.6.2-2 Show 4 moreShow less1.6.2-2build11.6.3-11.6.3-1ubuntu0.11.6.3-1ubuntu0.2 |
1.6.3-1ubuntu0.2+esm2 |
zncUbuntu:Pro:18.04:LTS |
before 1.6.6-1ubuntu0.2+esm2, plus listed versions 1.6.5-2build21.6.5-2build31.6.5-2build41.6.5-2build51.6.6-11.6.6-1ubuntu0.11.6.6-1ubuntu0.2 |
1.6.6-1ubuntu0.2+esm2 |
zncUbuntu:Pro:20.04:LTS |
before 1.7.5-4ubuntu0.1~esm2, plus listed versions 1.7.4-71.7.4-7build11.7.5-11.7.5-21.7.5-2build1 Show 5 moreShow less1.7.5-2build21.7.5-2build31.7.5-31.7.5-3build11.7.5-4 |
1.7.5-4ubuntu0.1~esm2 |
zncUbuntu:22.04:LTS |
before 1.8.2-2ubuntu0.1, plus listed versions 1.8.2-2build11.8.2-2build21.8.2-2build31.8.2-2build5 |
1.8.2-2ubuntu0.1 |
zncUbuntu:Pro:24.04:LTS |
before 1.9.0-2ubuntu0.1~esm2, plus listed versions 1.8.2-3.11.8.2-41.8.2-4build11.8.2-4build31.9.0-2build21.9.0-2build3 |
1.9.0-2ubuntu0.1~esm2 |
zncSUSE:Package Hub 15 SP6 |
before 1.9.1-bp156.2.3.1 | 1.9.1-bp156.2.3.1 |
zncopenSUSE:Leap 15.6 |
before 1.9.1-bp156.2.3.1 | 1.9.1-bp156.2.3.1 |
zncopenSUSE:Tumbleweed |
before 1.9.1-1.1 | 1.9.1-1.1 |
Public exploits
Links only. Every CVE stores no exploit code.
| Source | Link | Date |
|---|---|---|
| PoC in GitHub | ph1ns/CVE-2024-39844 | 2024-07-03 |
History
| Recorded | Changed | Sources |
|---|---|---|
| affected, aliases, references | OSV | |
| aliases | EUVD | |
| first indexed | CVE List, GitHub Advisories, NVD, OSV, PoC in GitHub |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2024-39844 is a critical vulnerability (CVSS 9.8) in Znc, published July 3, 2024. Public exploit code exists. EPSS puts the chance of exploitation in the next 30 days at 3.86%, the 90th percentile. Fixed in znc 1.9.1-r0.
References
wiki.znc.in/Category:ChangeLog
github.com/znc/znc/releases/tag/znc-1.9.1
openwall.com/lists/oss-security/2024/07/03/9
nvd.nist.gov/vuln/detail/CVE-2024-39844
Show 11 moreShow less
security.alpinelinux.org/vuln/CVE-2024-39844
security-tracker.debian.org/tracker/CVE-2024-39844
advisories.mageia.org/MGASA-2024-0257.html
bugs.mageia.org/show_bug.cgi?id=33364
ubuntu.com/security/CVE-2024-39844
cve.org/CVERecord?id=CVE-2024-39844
lists.opensuse.org/archives/list/[email protected]/thread/7QQ7R7LSWLXD4TDRUDSD57JQTEXMFSMH
bugzilla.suse.com/1227393
suse.com/security/cve/CVE-2024-39844