Linux KernelOperating system · Linux
CVE-2021-47511
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 · uneditedIn the Linux kernel, the following vulnerability has been resolved: ALSA: pcm: oss: Fix negative period/buffer sizes The period size calculation in OSS layer may receive a negative value as an error, but the code there assumes only the positive values and handle them with size_t. Due to that, a too big value may be passed to the lower layers. This patch changes the code to handle with ssize_t and adds the proper error checks appropriately.
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 analysisA detailed technical summary for this CVE is being prepared.
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
< 4.4.295>= 4.5, < 4.9.293>= 4.10, < 4.14.258>= 4.15, < 4.19.221>= 4.20, < 5.4.165>= 5.5, < 5.10.85>= 5.11, < 5.15.8= 5.16CVSS 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
- Local
- Complexity
- Low
- Privileges
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- None
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
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.
dbcve · scoped4.4.2954.9.2934.14.258
4.4.295 (for 4.4.x) | 4.9.293 (for 4.9.x) | 4.14.258 (for 4.14.x) | 4.19.221 (for 4.19.x)
- Identify the running kernel version using `uname -r`
- Determine which branch the current kernel version belongs to (4.4.x, 4.9.x, 4.14.x, or 4.19.x)
- For 4.4.x branch: upgrade to kernel version 4.4.295 or later
- For 4.9.x branch: upgrade to kernel version 4.9.293 or later
- For 4.14.x branch: upgrade to kernel version 4.14.258 or later
- For 4.19.x branch: upgrade to kernel version 4.19.221 or later
- Alternatively, apply the vendor patch commit 00a860678098fcd9fa8db2b5fb9d2ddf4776d4cc to the kernel source and recompile
Generated from the published advisory — verify against the referenced sources before acting.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2021-47511 — 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-2021-47511 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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- 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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