Linux KernelOperating system · Linux
CVE-2004-1056
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 · uneditedDirect Rendering Manager (DRM) driver in Linux kernel 2.6 does not properly check the DMA lock, which could allow remote attackers or local users to cause a denial of service (X Server crash) and possibly modify the video output.
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 confidenceThe Direct Rendering Manager (DRM) driver in Linux kernel 2.6 fails to properly validate the DMA lock before performing direct memory access operations. This missing validation creates a race condition that can allow unprivileged users or remote attackers to trigger X Server crashes (denial of service) and potentially manipulate video output by interfering with graphics hardware access.
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
Linux KernelOperating system
= 2.6.0= 2.6.1= 2.6.2= 2.6.3= 2.6.4= 2.6.5= 2.6.6= 2.6.7= 2.6.8= 2.6.9= 2.6.10= 2.6_test9_cvs
Ubuntu LinuxOperating system
= 4.1CVSS 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
- Partial
AV:N/AC:L/Au:N/C:N/I:P/A:P
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.
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Identify the running kernel versionRun 'uname -r' or check /proc/version to obtain the exact kernel version stringAffected if The version falls within 2.6.0 through 2.6.10, or is 2.6_test9_cvs, indicating it is in the affected range
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Determine if the DRM subsystem is activeRun 'lsmod | grep -i drm' to list loaded DRM-related kernel modules such as drm, i810, radeon, i915, or viaAffected if Any DRM module is loaded and the kernel version is in the affected range, as the vulnerability exists in the DRM driver code itself
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Verify if the X server is running with DRM supportCheck for running X processes with 'ps aux | grep X' and verify the presence of DRM device nodes at /dev/dri/ using 'ls -la /dev/dri/'Affected if X server is active and accessing DRM device nodes while using a vulnerable kernel version, creating the condition for the race condition to be exploitable
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Confirm the Ubuntu version if applicableFor Ubuntu systems, run 'cat /etc/lsb-release' or check /etc/ubuntu-version to identify the specific Ubuntu releaseAffected if The system is Ubuntu 4.1 and is running a vulnerable kernel, placing it within the affected product range
A system is affected if it runs a Linux kernel between 2.6.0 and 2.6.10 (or 2.6_test9_cvs), or Ubuntu 4.1, with the DRM subsystem and X server active, as the race condition in DMA lock validation only manifests when these conditions align.
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 the Linux kernel to a version that includes the corrected DMA lock checking in the DRM subsystem. For systems that cannot be immediately upgraded, consider restricting access to the X server and DRM device nodes to trusted users only.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 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 $3,808.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2004-1056 — 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-2004-1056 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
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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
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