FreeBSDOperating system
CVE-2005-2019
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedipfw in FreeBSD 5.4, when running on Symmetric Multi-Processor (SMP) or Uni Processor (UP) systems with the PREEMPTION kernel option enabled, does not sufficiently lock certain resources while performing table lookups, which can cause the cache results to be corrupted during multiple concurrent lookups, allowing remote attackers to bypass intended access restrictions.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · high confidenceipfw firewall in FreeBSD 5.4 has a race condition in table lookup operations. On SMP or UP systems with the PREEMPTION kernel option, insufficient locking during concurrent table lookups causes cache result corruption, allowing attackers to bypass firewall access restrictions.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data
FreeBSDOperating system
= 5.4CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Authentication
- None
- Confidentiality
- None
- Integrity
- Partial
- Availability
- None
AV:N/AC:L/Au:N/C:N/I:P/A:N
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
-
Confirm FreeBSD versionRun `uname -r` or check `/etc/os-release` to identify the installed FreeBSD versionAffected if The version is exactly 5.4 (FreeBSD 5.4)
-
Verify ipfw is in use with tablesRun `ipfw list` and check for table entries using `ipfw table all list`Affected if ipfw is actively configured and using table entries (tables 0-9999)
-
Check kernel PREEMPTION optionInspect the running kernel configuration via `sysctl kern.conftxt` or check the kernel config file in `/boot/kernel.conf` or `/usr/src/sys/i386/conf/KERNELNAME` for the PREEMPTION optionAffected if PREEMPTION is enabled in the kernel configuration (kernel contains 'options PREEMPTION' or equivalent)
-
Determine if system is SMP or uses preemptionRun `sysctl hw.ncpu` to check for multiple CPUs and `sysctl kern.preempt` to check preemption statusAffected if System has multiple CPUs (SMP) or preemption is active, and the kernel was built with PREEMPTION
A system is affected if it runs FreeBSD 5.4 with ipfw tables enabled on a kernel built with the PREEMPTION option, particularly on SMP systems where concurrent table lookups can cause cache corruption.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
From vendor dataUpgrade to a patched FreeBSD version or apply the vendor-supplied kernel patch that adds proper locking around table lookups; ensure PREEMPTION is disabled if patching is not immediately feasible.
Fix this in FreeBSD
Scoped from the published advisory
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $5,600.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2005-2019 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2005-2019 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
Be the first to add a field note for this CVE — a mitigation you’ve verified, a version caveat, or a link to a working fix. Sign in above to contribute.
A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.
- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
- No spam, self-promotion, credentials, or personal data