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NVD / CVE Program· CNA Linux

CVE-2021-47511: ALSA: pcm: oss: Fix negative period/buffer sizes

MediumCVSS 5.5 · v3.1—No exploit Fix available

Noroxi assessment

Priority: Monitor (action score 22/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.24% (FIRST EPSS).
  • Someone with local access to the system can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: Linux Linux 00a860678098fcd9fa8db2b5fb9d2ddf4776d4cc, 02b2b691b77cd7b951fa7b6c9d44d4e472cdc823, 502e1146873d870f87da3b8f93d6bf2de5f38d0c.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 00a860678098fcd9fa8db2b5fb9d2ddf4776d4cc, 02b2b691b77cd7b951fa7b6c9d44d4e472cdc823, 502e1146873d870f87da3b8f93d6bf2de5f38d0c or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In 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.

Published
May 24, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 15th percentile
CWE
—

Report tools

JSON

Action score

22

Monitor

Low priority for now.

CVSS
22 / 40 · 5.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
no
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-47511

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
linuxlinux kernel

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • linux linux kernelbefore 4.4.295
  • linux linux kernel4.5 and later · before 4.9.293
  • linux linux kernel4.10 and later · before 4.14.258
  • linux linux kernel4.15 and later · before 4.19.221
  • linux linux kernel4.20 and later · before 5.4.165
  • linux linux kernel5.5 and later · before 5.10.85
  • linux linux kernel5.11 and later · before 5.15.8
  • linux linux kernel5.16

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 2.6.12affected
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before be8869d388593e57223ad39297c8e54be632f2f2affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 502e1146873d870f87da3b8f93d6bf2de5f38d0caffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 8af815ab052eaf74addbbfb556d63ce2137c0e1baffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before f96c0959c1ee92adc911c10d6ec209af50105049affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before f12c8a7515f641885677960af450082569a87243affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 02b2b691b77cd7b951fa7b6c9d44d4e472cdc823affected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 00a860678098fcd9fa8db2b5fb9d2ddf4776d4ccaffected · git
    • 1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 and later · before 9d2479c960875ca1239bcb899f386970c13d9cfeaffected · git
    • before 2.6.12not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.15.15-15.15.15-1
SUSE:Linux Enterprise Live Patching 12 SP5kgraft-patch-SLE12-SP5_Update_53before 14-2.114-2.1
SUSE:Linux Enterprise Live Patching 12 SP5kgraft-patch-SLE12-SP5_Update_54before 13-2.113-2.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-defaultbefore 3.0.101-108.156.13.0.101-108.156.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-ec2before 3.0.101-108.156.13.0.101-108.156.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-sourcebefore 3.0.101-108.156.13.0.101-108.156.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-symsbefore 3.0.101-108.156.13.0.101-108.156.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-tracebefore 3.0.101-108.156.13.0.101-108.156.1
SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREkernel-xenbefore 3.0.101-108.156.13.0.101-108.156.1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-31431crypto: algif_aead - Revert to operating out-of-placeKEV
    90Now
  • CVE-2022-0847A flaw was found in the way the "flags" member of the new pipe buffer structure was lacking proper initialization in copy_page_to_iter_pipe…KEV
    89Now
  • CVE-2021-22555Heap Out-Of-Bounds Write in Netfilter IP6T_SO_SET_REPLACEKEV
    85Now

Published before and after this one in the same product

  • ← EarlierCVE-2021-47509May 24, 2024 · ALSA: pcm: oss: Limit the period size to 16MB
    22Monitor
  • ← EarlierCVE-2021-47510May 24, 2024 · btrfs: fix re-dirty process of tree-log nodes
    22Monitor
  • Later →CVE-2021-47512May 24, 2024 · net/sched: fq_pie: prevent dismantle issue
    22Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux00a860678098fcd9fa8db2b5fb9d2ddf4776d4ccVendor (CNA)
Linux Linux02b2b691b77cd7b951fa7b6c9d44d4e472cdc823Vendor (CNA)
Linux Linux502e1146873d870f87da3b8f93d6bf2de5f38d0cVendor (CNA)
Linux Linux8af815ab052eaf74addbbfb556d63ce2137c0e1bVendor (CNA)
Linux Linux9d2479c960875ca1239bcb899f386970c13d9cfeVendor (CNA)
Linux Linuxbe8869d388593e57223ad39297c8e54be632f2f2Vendor (CNA)
Linux Linuxf12c8a7515f641885677960af450082569a87243Vendor (CNA)
Linux Linuxf96c0959c1ee92adc911c10d6ec209af50105049Vendor (CNA)
debian:linux5.15.15-1 · Debian:12Package registry (OSV)
suse:kernel-default3.0.101-108.156.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-ec23.0.101-108.156.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-source3.0.101-108.156.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-syms3.0.101-108.156.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-trace3.0.101-108.156.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kernel-xen3.0.101-108.156.1 · SUSE:Linux Enterprise Server 11 SP4 LTSS EXTREME COREPackage registry (OSV)
suse:kgraft-patch-SLE12-SP5_Update_5314-2.1 · SUSE:Linux Enterprise Live Patching 12 SP5Package registry (OSV)
suse:kgraft-patch-SLE12-SP5_Update_5413-2.1 · SUSE:Linux Enterprise Live Patching 12 SP5Package registry (OSV)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

National notice (Türkiye Cybersecurity Directorate / USOM)

Official security notices citing this record; remediation advice is on the agency's page.

All national notices →

Technical details

Attack conditions

  • Someone with local access to the system can trigger it.
  • A low-privileged account is enough.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (7 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records