CVE-2005-4351: The securelevels implementation in FreeBSD 7.0 and earlier, OpenBSD up to 3.8, DragonFly up to 1.2, and Linux

Q: How do I fix CVE-2005-4351?

dragonfly: upgrade to newer than 1.2; freebsd: upgrade to newer than 6.0; linux kernel: upgrade to newer than 2.6.15. Exact commands for each OS are on this page.

Q: Is CVE-2005-4351 being exploited?

CVE-2005-4351 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-2005-4351 affect?

CVE-2005-4351 affects dragonfly, freebsd, linux kernel. Severity is medium (CVSS 4.3). The securelevels implementation in FreeBSD 7.0 and earlier, OpenBSD up to 3.8, DragonFly up to 1.2, and Linux up to 2.6.15 allows root users to bypass immutable settings for files by mounting another filesystem that masks the immutable file

Q: How urgent is CVE-2005-4351?

Priority 34/100. Public exploit reference; On your watchlist

Routine

MEDIUM 4.3WATCHLISTUPGRADEUPGRADEUPGRADE

CVE-2005-4351 is a medium-severity flaw (CVSS 4.3) affecting dragonfly, freebsd, linux kernel. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

The securelevels implementation in FreeBSD 7.0 and earlier, OpenBSD up to 3.8, DragonFly up to 1.2, and Linux up to 2.6.15 allows root users to bypass immutable settings for files by mounting another filesystem that masks the immutable files while the system is running.

Why this priority

Public exploit reference
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	4.3 (Medium)
EPSS exploit chance	0.4% (top 63%)
CISA exploited list	No
Published	2005-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: dragonfly · freebsd · linux · openbsd

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

Am I affected?

Timeline

2005-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:18 UTCUpdated Record last modified

dragonfly dragonfly UPGRADE

Affected: <= 1.2

Fixed in: newer than 1.2

Safe to downgrade to: no unaffected older release

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.

freebsd freebsd UPGRADE

Affected: <= 6.0 · 7.0 current

Fixed in: newer than 6.0

Safe to downgrade to: no unaffected older release

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.

linux linux kernel UPGRADE

Affected: <= 2.6.15

Fixed in: newer than 2.6.15

Safe to downgrade to: no unaffected older release

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.

openbsd openbsd UPGRADE

Affected: <= 3.8

Fixed in: newer than 3.8

Safe to downgrade to: no unaffected older release

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.

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-2005-4351?

dragonfly: upgrade to newer than 1.2; freebsd: upgrade to newer than 6.0; linux kernel: upgrade to newer than 2.6.15. Exact commands for each OS are on this page.

Is CVE-2005-4351 being exploited?

CVE-2005-4351 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-2005-4351 affect?

CVE-2005-4351 affects dragonfly, freebsd, linux kernel. Severity is medium (CVSS 4.3). The securelevels implementation in FreeBSD 7.0 and earlier, OpenBSD up to 3.8, DragonFly up to 1.2, and Linux up to 2.6.15 allows root users to bypass immutable settings for files by mounting another filesystem that masks the immutable file

How urgent is CVE-2005-4351?

Priority 34/100. Public exploit reference; On your watchlist

Software pages

Linux kernel vulnerabilities

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References

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