CVE-2018-1000178: A heap corruption of type CWE-120 exists in quassel version 0.12.4 in quasselcore in void DataStreamPeer::proc

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CRITICAL 9.8REMOTEWATCHLISTDOWNGRADEMITIGATE

CVE-2018-1000178 is a critical-severity flaw (CVSS 9.8) affecting quassel, debian linux. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A heap corruption of type CWE-120 exists in quassel version 0.12.4 in quasselcore in void DataStreamPeer::processMessage(const QByteArray &msg) datastreampeer.cpp line 62 that allows an attacker to execute code remotely.

Why this priority

Critical severity
EPSS top 9%: very likely to be exploited
Public exploit reference
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	4.1% (top 9%)
CISA exploited list	No
Weakness	CWE-787
Published	2018-05-08
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: debian · quassel-irc

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-05-08 15:29 UTCPublished CVE record published
2026-06-17 01:32 UTCUpdated Record last modified

quassel-irc quassel DOWNGRADE

Affected: 0.12.4

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.12.4

1. Check installed version

apt-cache policy quassel || rpm -q quassel || quassel --version

2. No fixed release: DOWNGRADE to a release before 0.12.4 (Debian / Ubuntu)

apt-cache madison quassel sudo apt install quassel=<VERSION_BEFORE_0.12.4> sudo apt-mark hold quassel

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list quassel sudo dnf downgrade quassel-<VERSION_BEFORE_0.12.4> sudo dnf versionlock add quassel

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

debian debian linux MITIGATE

Affected: 7.0 · 8.0 · 9.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Exact fixes by distribution

A distro patch exists: prefer upgrading over downgrading.

Fedora 46 · librepo · FIXED · 1.21.3-1.fc46 · FEDORA-2026-c502136ca7 · source

sudo dnf upgrade --advisory=FEDORA-2026-c502136ca7

Ubuntu 22.04 · quassel · NOT AFFECTED

Ubuntu 20.04 · quassel · NOT AFFECTED

Ubuntu 24.04 · quassel · NOT AFFECTED

Ubuntu 24.10 · quassel · NOT AFFECTED

Ubuntu 25.04 · quassel · NOT AFFECTED

Debian 12 · quassel · FIXED · 1:0.12.5-1

sudo apt update && sudo apt install --only-upgrade quassel dpkg --compare-versions "$(dpkg-query -W -f='${Version}' quassel)" ge "1:0.12.5-1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · quassel · FIXED · 1:0.12.5-1

sudo apt update && sudo apt install --only-upgrade quassel dpkg --compare-versions "$(dpkg-query -W -f='${Version}' quassel)" ge "1:0.12.5-1" && echo PATCHED || echo STILL-VULNERABLE

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2018-1000178?

quassel: downgrade or apply the listed mitigation; debian linux: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2018-1000178 being exploited?

CVE-2018-1000178 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2018-1000178 affect?

CVE-2018-1000178 affects quassel, debian linux. Severity is critical (CVSS 9.8). A heap corruption of type CWE-120 exists in quassel version 0.12.4 in quasselcore in void DataStreamPeer::processMessage(const QByteArray &msg) datastreampeer.cpp line 62 that allows an attacker to execute code remotely.

How urgent is CVE-2018-1000178?

Priority 72/100. Critical severity; EPSS top 9%: very likely to be exploited; Public exploit reference; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Debian vulnerabilities

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References

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