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NVD / CVE Program· CNA Linux

CVE-2021-47320: nfs: fix acl memory leak of posix_acl_create()

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: 0.25% (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 0704f617040c397ae73c1f88f3956787ec5d6529, 1fcb6fcd74a222d9ead54d405842fc763bb86262, 2e3960f276b4574a9bb0dfa31a7497302f6363b2.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0704f617040c397ae73c1f88f3956787ec5d6529, 1fcb6fcd74a222d9ead54d405842fc763bb86262, 2e3960f276b4574a9bb0dfa31a7497302f6363b2 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: nfs: fix acl memory leak of posix_acl_create() When looking into another nfs xfstests report, I found acl and default_acl in nfs3_proc_create() and nfs3_proc_mknod() error paths are possibly leaked. Fix them in advance.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
May 21, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 17th percentile

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-2021-47320

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 kernel3.14 and later · before 4.4.276
  • linux linux kernel4.5 and later · before 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 5.4.134
  • linux linux kernel5.5 and later · before 5.10.52
  • linux linux kernel5.11 and later · before 5.12.19
  • linux linux kernel5.13 and later · before 5.13.4

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

    • 3.14affected
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before 2e3960f276b4574a9bb0dfa31a7497302f6363b2affected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before cef9d9acb7c80ed6bace894b6334557fd493863baffected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before 8a2b308a54c5ec224fedc753617f99b29ffcd883affected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before 0704f617040c397ae73c1f88f3956787ec5d6529affected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before d0b32dc1409f7e65e4fcc34e236462268e69a357affected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before 4b515308ab875c7e8ada8e606fe0c64762da5ed4affected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before c8fc86e9df6a6a03f5a8e15a3b7a5c75fd05aa38affected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before 687cf32865b2d6960214bce523f2afac58dd3cd2affected · git
    • 013cdf1088d7235da9477a2375654921d9b9ba9f and later · before 1fcb6fcd74a222d9ead54d405842fc763bb86262affected · git

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-2021-47318May 21, 2024 · arch_topology: Avoid use-after-free for scale_freq_data
    31Monitor
  • ← EarlierCVE-2021-47319May 21, 2024 · virtio-blk: Fix memory leak among suspend/resume procedure
    22Monitor
  • Later →CVE-2021-47321May 21, 2024 · watchdog: Fix possible use-after-free by calling del_timer_sync()
    31Monitor

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 Linux0704f617040c397ae73c1f88f3956787ec5d6529Vendor (CNA)
Linux Linux1fcb6fcd74a222d9ead54d405842fc763bb86262Vendor (CNA)
Linux Linux2e3960f276b4574a9bb0dfa31a7497302f6363b2Vendor (CNA)
Linux Linux4b515308ab875c7e8ada8e606fe0c64762da5ed4Vendor (CNA)
Linux Linux687cf32865b2d6960214bce523f2afac58dd3cd2Vendor (CNA)
Linux Linux8a2b308a54c5ec224fedc753617f99b29ffcd883Vendor (CNA)
Linux Linuxc8fc86e9df6a6a03f5a8e15a3b7a5c75fd05aa38Vendor (CNA)
Linux Linuxcef9d9acb7c80ed6bace894b6334557fd493863bVendor (CNA)
Linux Linuxd0b32dc1409f7e65e4fcc34e236462268e69a357Vendor (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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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)

CWE-401 · Missing Release of Memory after Effective Lifetime

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 (8 more)

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

All records