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NVD / CVE Program· CNA Linux

CVE-2024-56755: netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING

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: 0.20% (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 22f9400a6f3560629478e0a64247b8fcc811a24d, 539fabba965e119b98066fc6ba5257b5eaf4eda2, 8beb682cc9a0798a280bbb95e3e41617237090b2; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1; azl3 kernel 6.6.64.2-1 on Azure Linux 3.0 6.6.64.2-1.

Low priority for now. Upgrade to Linux Linux 22f9400a6f3560629478e0a64247b8fcc811a24d, 539fabba965e119b98066fc6ba5257b5eaf4eda2, 8beb682cc9a0798a280bbb95e3e41617237090b2; azl3 kernel 6.6.57.1-7 on Azure Linux 3.0 6.6.64.2-1; azl3 kernel 6.6.64.2-1 on Azure Linux 3.0 6.6.64.2-1 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: netfs/fscache: Add a memory barrier for FSCACHE_VOLUME_CREATING In fscache_create_volume(), there is a missing memory barrier between the bit-clearing operation and the wake-up operation. This may cause a situation where, after a wake-up, the bit-clearing operation hasn't been detected yet, leading to an indefinite wait. The triggering process is as follows: [cookie1] [cookie2] [volume_work] fscache_perform_lookup fscache_create_volume fscache_perform_lookup fscache_create_volume fscache_create_volume_work cachefiles_acquire_volume clear_and_wake_up_bit test_and_set_bit test_and_set_bit goto maybe_wait goto no_wait In the above process, cookie1 and cookie2 has the same volume. When cookie1 enters the -no_wait- process, it will clear the bit and wake up the waiting process. If a barrier is missing, it may cause cookie2 to remain in the -wait- process indefinitely. In commit 3288666c7256 ("fscache: Use clear_and_wake_up_bit() in fscache_create_volume_work()"), barriers were added to similar operations in fscache_create_volume_work(), but fscache_create_volume() was missed. By combining the clear and wake operations into clear_and_wake_up_bit() to fix this issue.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Dec 29, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 10th 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

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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 kernel5.17 and later · before 6.1.120
  • linux linux kernel6.2 and later · before 6.6.64
  • linux linux kernel6.7 and later · before 6.11.11
  • linux linux kernel6.12 and later · before 6.12.2

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

    • 5.17affected
    • bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 and later · before ddab02607eed9e415dc62fde421d4329e5345315affected · git
    • bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 and later · before 539fabba965e119b98066fc6ba5257b5eaf4eda2affected · git
    • bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 and later · before 8beb682cc9a0798a280bbb95e3e41617237090b2affected · git
    • bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 and later · before 8cc1df3113cb71a0df2c46dd5b102c9e11c8a8c6affected · git
    • bfa22da3ed652aa15acd4246fa13a0de6dbe4a59 and later · before 22f9400a6f3560629478e0a64247b8fcc811a24daffected · git
    • before 5.17not affected · semver
    • 6.1.120 and later · up to and including 6.1.*not affected · semver
    • 6.6.64 and later · up to and including 6.6.*not affected · semver
    • 6.11.11 and later · up to and including 6.11.*not affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.123-16.1.123-1
Debian:13linuxbefore 6.12.3-16.12.3-1

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-2024-56753Dec 29, 2024 · drm/amdgpu/gfx9: Add Cleaner Shader Deinitialization in gfx_v9_0 Module
    22Monitor
  • ← EarlierCVE-2024-56754Dec 29, 2024 · crypto: caam - Fix the pointer passed to caam_qi_shutdown()
    22Monitor
  • Later →CVE-2024-56756Dec 29, 2024 · nvme-pci: fix freeing of the HMB descriptor table
    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 Linux22f9400a6f3560629478e0a64247b8fcc811a24dVendor (CNA)
Linux Linux539fabba965e119b98066fc6ba5257b5eaf4eda2Vendor (CNA)
Linux Linux8beb682cc9a0798a280bbb95e3e41617237090b2Vendor (CNA)
Linux Linux8cc1df3113cb71a0df2c46dd5b102c9e11c8a8c6Vendor (CNA)
Linux Linuxddab02607eed9e415dc62fde421d4329e5345315Vendor (CNA)
azl3 kernel 6.6.57.1-7 on Azure Linux 3.06.6.64.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.64.2-1 on Azure Linux 3.06.6.64.2-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.123-1 · 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).

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 (5 more)

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

All records