CVE-2012-5854: Heap-based buffer overflow in WeeChat 0.3.6 through 0.3.9 allows remote attackers to cause a denial of service

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HIGH 7.5DOWNGRADE

CVE-2012-5854 is a high-severity flaw (CVSS 7.5) affecting weechat. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap-based buffer overflow in WeeChat 0.3.6 through 0.3.9 allows remote attackers to cause a denial of service (crash or hang) and possibly execute arbitrary code via crafted IRC colors that are not properly decoded.

Why this priority

High severity
EPSS top 7%: very likely to be exploited

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	5.5% (top 7%)
CISA exploited list	No
Weakness	CWE-119
Published	2012-11-19
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: flashtux

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2012-11-19 12:10 UTCPublished CVE record published
2026-06-16 23:47 UTCUpdated Record last modified

flashtux weechat DOWNGRADE

Affected: 0.3.6 · 0.3.7 · 0.3.8 · 0.3.9

Fixed in: no fixed release known

Safe to downgrade to: a release before 0.3.6

1. Check installed version

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

2. No fixed release: DOWNGRADE to a release before 0.3.6 (Debian / Ubuntu)

apt-cache madison weechat sudo apt install weechat=<VERSION_BEFORE_0.3.6> sudo apt-mark hold weechat

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

dnf --showduplicates list weechat sudo dnf downgrade weechat-<VERSION_BEFORE_0.3.6> sudo dnf versionlock add weechat

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.

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-2012-5854?

weechat: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2012-5854 being exploited?

CVE-2012-5854 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-2012-5854 affect?

CVE-2012-5854 affects weechat. Severity is high (CVSS 7.5). Heap-based buffer overflow in WeeChat 0.3.6 through 0.3.9 allows remote attackers to cause a denial of service (crash or hang) and possibly execute arbitrary code via crafted IRC colors that are not properly decoded.

How urgent is CVE-2012-5854?

Priority 49/100. High severity; EPSS top 7%: very likely to be exploited

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References

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