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CVE-2024-56549· NVD / CVE Program· CNA Linux

cachefiles: Fix NULL pointer dereference in object->file

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: 0.23% (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 31ad74b20227ce6b40910ff78b1c604e42975cf1, 785408bbafcfa24c9fc5b251f03fd0780ce182bd, 9582c7664103c9043e80a78f5c382aa6bdd67418; azl3 kernel 6.6.78.1-1 on Azure Linux 3.0 6.6.78.1-1; azl3 kernel 6.6.92.2-1 on Azure Linux 3.0 6.6.78.1-1.
  • Severity is disputed: the assigning authority (CNA) scores it 7.8, NVD 5.5.

Low priority for now. Upgrade to Linux Linux 31ad74b20227ce6b40910ff78b1c604e42975cf1, 785408bbafcfa24c9fc5b251f03fd0780ce182bd, 9582c7664103c9043e80a78f5c382aa6bdd67418; azl3 kernel 6.6.78.1-1 on Azure Linux 3.0 6.6.78.1-1; azl3 kernel 6.6.92.2-1 on Azure Linux 3.0 6.6.78.1-1 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: cachefiles: Fix NULL pointer dereference in object->file At present, the object->file has the NULL pointer dereference problem in ondemand-mode. The root cause is that the allocated fd and object->file lifetime are inconsistent, and the user-space invocation to anon_fd uses object->file. Following is the process that triggers the issue: [write fd] [umount] cachefiles_ondemand_fd_write_iter fscache_cookie_state_machine cachefiles_withdraw_cookie if (!file) return -ENOBUFS cachefiles_clean_up_object cachefiles_unmark_inode_in_use fput(object->file) object->file = NULL // file NULL pointer dereference! __cachefiles_write(..., file, ...) Fix this issue by add an additional reference count to the object->file before write/llseek, and decrement after it finished.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Dec 27, 2024
Updated
Oct 15, 2026
EPSS
0.2% · 13th 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
total

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
5.5
CNA · Linux
7.8
2.3 point gap

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

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

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-2024-56549

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 kernel5.19 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

    • 5.19affected
    • c8383054506c77b814489c09877b5db83fd4abf2 and later · before d6bba3ece960129a553d4b16f1b00c884dc0993aaffected · git
    • c8383054506c77b814489c09877b5db83fd4abf2 and later · before 785408bbafcfa24c9fc5b251f03fd0780ce182bdaffected · git
    • c8383054506c77b814489c09877b5db83fd4abf2 and later · before f98770440c9bc468e2fd878212ec9526dbe08293affected · git
    • c8383054506c77b814489c09877b5db83fd4abf2 and later · before 9582c7664103c9043e80a78f5c382aa6bdd67418affected · git
    • c8383054506c77b814489c09877b5db83fd4abf2 and later · before 31ad74b20227ce6b40910ff78b1c604e42975cf1affected · git
    • before 5.19not affected · semver
    • 6.1.129 and later · up to and including 6.1.*not affected · semver
    • 6.6.78 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:11linux-6.1before 6.1.129-1~deb11u16.1.129-1~deb11u1
Debian:12linuxbefore 6.1.129-16.1.129-1
Debian:13linuxbefore 6.12.3-16.12.3-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-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
  • CVE-2016-5195Race condition in mm/gup.c in the Linux kernel 2.x through 4.x before 4.8.3 allows local users to gain privileges by leveraging incorrect haKEV
    83Now

Published before and after this one in the same product

  • ← EarlierCVE-2024-56544Dec 27, 2024 · udmabuf: change folios array from kmalloc to kvmalloc
    22Monitor
  • ← EarlierCVE-2024-56545Dec 27, 2024 · HID: hyperv: streamline driver probe to avoid devres issues
    22Monitor
  • Later →CVE-2024-56569Dec 27, 2024 · ftrace: Fix regression with module command in stack_trace_filter
    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 Linux31ad74b20227ce6b40910ff78b1c604e42975cf1Vendor (CNA)
Linux Linux785408bbafcfa24c9fc5b251f03fd0780ce182bdVendor (CNA)
Linux Linux9582c7664103c9043e80a78f5c382aa6bdd67418Vendor (CNA)
Linux Linuxd6bba3ece960129a553d4b16f1b00c884dc0993aVendor (CNA)
Linux Linuxf98770440c9bc468e2fd878212ec9526dbe08293Vendor (CNA)
azl3 kernel 6.6.78.1-1 on Azure Linux 3.06.6.78.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
azl3 kernel 6.6.92.2-1 on Azure Linux 3.06.6.78.1-1 · CBL-Mariner ReleasesMicrosoft (MSRC)
debian:linux6.1.129-1 · Debian:12Package registry (OSV)
debian:linux-6.16.1.129-1~deb11u1 · Debian:11Package 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).

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-476 · NULL Pointer Dereference

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. SSVC exploitation— → none
  2. 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