CVE-2013-6404: Quassel core (server daemon) in Quassel IRC before 0.9.2 does not properly verify the user ID when accessing u

Q: How do I fix CVE-2013-6404?

quassel irc: upgrade to newer than 0.9.1. Exact commands for each OS are on this page.

Q: Is CVE-2013-6404 being exploited?

CVE-2013-6404 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2013-6404 affect?

CVE-2013-6404 affects quassel irc. Severity is medium (CVSS 4.0). Quassel core (server daemon) in Quassel IRC before 0.9.2 does not properly verify the user ID when accessing user backlogs, which allows remote authenticated users to read other users' backlogs via the bufferid in (1) 16/select_buffer_by_id

Q: How urgent is CVE-2013-6404?

Priority 39/100. Public exploit reference

Routine

MEDIUM 4.0UPGRADE

CVE-2013-6404 is a medium-severity flaw (CVSS 4.0) affecting quassel irc. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Quassel core (server daemon) in Quassel IRC before 0.9.2 does not properly verify the user ID when accessing user backlogs, which allows remote authenticated users to read other users' backlogs via the bufferid in (1) 16/select_buffer_by_id.sql, (2) 16/select_buffer_by_id.sql, and (3) 16/select_buffer_by_id.sql in core/SQL/PostgreSQL/.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	4.0 (Medium)
EPSS exploit chance	2.1% (top 19%)
CISA exploited list	No
Weakness	CWE-264
Published	2013-12-09
Last modified	2026-06-17

Publisher (CNA): Red Hat, Inc. · Vendor: quassel-irc

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

Am I affected?

Timeline

2013-12-09 16:36 UTCPublished CVE record published
2026-06-17 00:00 UTCUpdated Record last modified

quassel-irc quassel irc UPGRADE

Affected: <= 0.9.1 · 0.9.0

Fixed in: newer than 0.9.1

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to newer than 0.9.1 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade quassel-irc

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade quassel-irc

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

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-2013-6404?

quassel irc: upgrade to newer than 0.9.1. Exact commands for each OS are on this page.

Is CVE-2013-6404 being exploited?

CVE-2013-6404 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-2013-6404 affect?

CVE-2013-6404 affects quassel irc. Severity is medium (CVSS 4.0). Quassel core (server daemon) in Quassel IRC before 0.9.2 does not properly verify the user ID when accessing user backlogs, which allows remote authenticated users to read other users' backlogs via the bufferid in (1) 16/select_buffer_by_id

How urgent is CVE-2013-6404?

Priority 39/100. Public exploit reference

Software pages

PostgreSQL vulnerabilities

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References

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