Linux KernelOperating system · Linux
CVE-2007-4311
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 · uneditedThe xfer_secondary_pool function in drivers/char/random.c in the Linux kernel 2.4 before 2.4.35 performs reseed operations on only the first few bytes of a buffer, which might make it easier for attackers to predict the output of the random number generator, related to incorrect use of the sizeof operator.
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 confidenceIn the Linux kernel 2.4.x before 2.4.35, the xfer_secondary_pool function in drivers/char/random.c incorrectly uses the sizeof operator, causing the random number generator reseed operation to process only the first few bytes of the buffer instead of the full buffer. This partial reseeding weakens the entropy mixing and could make the RNG output more predictable.
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
<= 2.4.34CVSS 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
- M
- Authentication
- None
- Confidentiality
- Partial
- Integrity
- Partial
- Availability
- Partial
AV:N/AC:M/Au:N/C:P/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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Check the running kernel versionRun `uname -r` or `cat /proc/version` to identify the kernel versionAffected if The version shows 2.4.x and is 2.4.34 or lower
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Confirm the kernel branch is 2.4.xVerify the version output begins with 2.4 (not 2.6 or later)Affected if The kernel major.minor version is 2.4.x
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Identify exact 2.4.x version numberCompare the full version number (e.g., 2.4.33, 2.4.30, 2.4.20) against the affected rangeAffected if The version is 2.4.34 or any version below 2.4.35 (e.g., 2.4.33, 2.4.32, etc.)
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Locate the affected source file (if kernel sources available)Check for the file drivers/char/random.c in the kernel source tree and examine the xfer_secondary_pool function for the sizeof usageAffected if The source file contains the buggy sizeof implementation that processes only a partial buffer instead of the full buffer during reseed
A system is affected if it runs any Linux kernel 2.4.x version numbered 2.4.34 or lower, since only those versions contain the flawed sizeof calculation in the random number generator's xfer_secondary_pool function.
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 Linux kernel 2.4.35 or later, which corrects the sizeof operator usage to properly reseed the entire buffer. For legacy systems that cannot upgrade, backport the specific patch that corrects the sizeof calculation in xfer_secondary_pool.
Fix this in Linux Kernel
Scoped from the published advisory
- Consultation2.0 h
- Implementation4.0 h
- Testing2.0 h
- Review / QA1.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $2,560.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2007-4311 — 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-2007-4311 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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- Version or environment caveats, and links to real fixes
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