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NVD / CVE Program· CNA Linux

CVE-2021-47336: smackfs: restrict bytes count in smk_set_cipso()

Noroxi assessment

Priority: Monitor (action score 31/100)

  • 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 135122f174c357b7a3e58f40fa5792156c5e93e6, 258fd821f69378453c071b9dd767b298810fc766, 3780348c1a0e14ffefcaf1fc521f815bcaac94b0.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 135122f174c357b7a3e58f40fa5792156c5e93e6, 258fd821f69378453c071b9dd767b298810fc766, 3780348c1a0e14ffefcaf1fc521f815bcaac94b0 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: smackfs: restrict bytes count in smk_set_cipso() Oops, I failed to update subject line. From 07571157c91b98ce1a4aa70967531e64b78e8346 Mon Sep 17 00:00:00 2001 Date: Mon, 12 Apr 2021 22:25:06 +0900 Subject: [PATCH] smackfs: restrict bytes count in smk_set_cipso() Commit 7ef4c19d245f3dc2 ("smackfs: restrict bytes count in smackfs write functions") missed that count > SMK_CIPSOMAX check applies to only format == SMK_FIXED24_FMT case.

HighCVSS 7.8 · v3.1—No exploit Fix available
Published
May 21, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 15th percentile
CWE
—

Report tools

JSON

Action score

31

Monitor

Low priority for now.

CVSS
31 / 40 · 7.8 / 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-2021-47336

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 4.9.276
  • linux linux kernel4.10 and later · before 4.14.240
  • linux linux kernel4.15 and later · before 4.19.198
  • linux linux kernel4.20 and later · before 5.4.133
  • linux linux kernel5.5 and later · before 5.10.51
  • linux linux kernel5.11 and later · before 5.12.18
  • linux linux kernel5.13 and later · before 5.13.3

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

    • 3.5affected
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before 5f9880403e6b71d56924748ba331daf836243fcaaffected · git
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before 5c2dca9a7a7ff6a2df34158903515e2e4fd3d2b2affected · git
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before cbd87ba6a13891acf6180783f8234a8b7a3e3d4daffected · git
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before 135122f174c357b7a3e58f40fa5792156c5e93e6affected · git
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before 3780348c1a0e14ffefcaf1fc521f815bcaac94b0affected · git
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before 8f5c773a2871cf446e3f36b2834fb25bbb28512baffected · git
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before 258fd821f69378453c071b9dd767b298810fc766affected · git
    • f7112e6c9abf1c70f001dcf097c1d6e218a93f5c and later · before 49ec114a6e62d8d320037ce71c1aaf9650b3cafdaffected · git
    • before 3.5not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 5.14.6-15.14.6-1

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-2021-47334May 21, 2024 · misc/libmasm/module: Fix two use after free in ibmasm_init_one
    31Monitor
  • ← EarlierCVE-2021-47335May 21, 2024 · f2fs: fix to avoid racing on fsync_entry_slab by multi filesystem instances
    22Monitor
  • Later →CVE-2021-47337May 21, 2024 · scsi: core: Fix bad pointer dereference when ehandler kthread is invalid
    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 Linux135122f174c357b7a3e58f40fa5792156c5e93e6Vendor (CNA)
Linux Linux258fd821f69378453c071b9dd767b298810fc766Vendor (CNA)
Linux Linux3780348c1a0e14ffefcaf1fc521f815bcaac94b0Vendor (CNA)
Linux Linux49ec114a6e62d8d320037ce71c1aaf9650b3cafdVendor (CNA)
Linux Linux5c2dca9a7a7ff6a2df34158903515e2e4fd3d2b2Vendor (CNA)
Linux Linux5f9880403e6b71d56924748ba331daf836243fcaVendor (CNA)
Linux Linux8f5c773a2871cf446e3f36b2834fb25bbb28512bVendor (CNA)
Linux Linuxcbd87ba6a13891acf6180783f8234a8b7a3e3d4dVendor (CNA)
debian:linux5.14.6-1 · Debian:12Package 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
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

—

CVSS vector

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