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NVD / CVE Program· CNA Linux

CVE-2024-39276: ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find()

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 0c0b4a49d3e7f49690a6827a41faeffad5df7e21, 4.15, 4.19.316.
  • Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 0c0b4a49d3e7f49690a6827a41faeffad5df7e21, 4.15, 4.19.316 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: ext4: fix mb_cache_entry's e_refcnt leak in ext4_xattr_block_cache_find() Syzbot reports a warning as follows: ============================================ WARNING: CPU: 0 PID: 5075 at fs/mbcache.c:419 mb_cache_destroy+0x224/0x290 Modules linked in: CPU: 0 PID: 5075 Comm: syz-executor199 Not tainted 6.9.0-rc6-gb947cc5bf6d7 RIP: 0010:mb_cache_destroy+0x224/0x290 fs/mbcache.c:419 Call Trace: <TASK> ext4_put_super+0x6d4/0xcd0 fs/ext4/super.c:1375 generic_shutdown_super+0x136/0x2d0 fs/super.c:641 kill_block_super+0x44/0x90 fs/super.c:1675 ext4_kill_sb+0x68/0xa0 fs/ext4/super.c:7327 [...] ============================================ This is because when finding an entry in ext4_xattr_block_cache_find(), if ext4_sb_bread() returns -ENOMEM, the ce's e_refcnt, which has already grown in the __entry_find(), won't be put away, and eventually trigger the above issue in mb_cache_destroy() due to reference count leakage. So call mb_cache_entry_put() on the -ENOMEM error branch as a quick fix.

MediumCVSS 5.5 · v3.1—No exploit Fix available
Published
Jun 25, 2024
Updated
Jun 17, 2026
EPSS
0.2% · 14th 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.

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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 kernel4.14.92 and later · before 4.15
  • linux linux kernel4.19.14 and later · before 4.19.316
  • linux linux kernel4.20.1 and later · up to 5.4.278 inclusive
  • linux linux kernel5.5 and later · up to 5.15.161 inclusive
  • linux linux kernel5.16 and later · up to 6.1.94 inclusive
  • linux linux kernel6.2 and later · up to 6.6.34 inclusive
  • linux linux kernel6.7 and later · up to 6.9.5 inclusive

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

    • 9da1f6d06b7a6d068e68fcfd7cbbf6b586d888e1, 81313ed2c705d958744882a269bf4a5e3ddec95e, 5.0affected
    • b878c8a7f08f0c225b6a46ba1ac867e9c5d17807 and later · before 9ad75e78747b5a50dc5a52f0f8e92e920a653f16affected · git
    • fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and later · before 896a7e7d0d555ad8b2b46af0c2fa7de7467f9483affected · git
    • fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and later · before 76dc776153a47372719d664e0fc50d6355791abbaffected · git
    • fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and later · before 681ff9a09accd8a4379f8bd30b7a1641ee19bb3eaffected · git
    • fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and later · before e941b712e758f615d311946bf98216e79145ccd9affected · git
    • fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and later · before a95df6f04f2c37291adf26a74205cde0314d4577affected · git
    • fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and later · before b37c0edef4e66fb21a2fbc211471195a383e5ab8affected · git
    • fb265c9cb49e2074ddcdd4de99728aefdd3b3592 and later · before 0c0b4a49d3e7f49690a6827a41faeffad5df7e21affected · git
    • 4.19.14 and later · before 4.19.316affected · semver

Package-level exposure

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

EcosystemPackageAffected rangeFix
Debian:12linuxbefore 6.1.94-16.1.94-1
Debian:13linuxbefore 6.9.7-16.9.7-1
Red Hat:rhel_eus:9.4::appstreambpftool-debuginfobefore 0:7.3.0-427.57.1.el9_40:7.3.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-64k-debug-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-64k-debug-develbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-64k-debug-devel-matchedbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-64k-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-64k-develbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-64k-devel-matchedbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debug-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debug-develbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debug-devel-matchedbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debuginfo-common-aarch64before 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debuginfo-common-ppc64lebefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debuginfo-common-s390xbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-debuginfo-common-x86_64before 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-develbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-devel-matchedbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-docbefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-rt-debug-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-rt-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-tools-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4
Red Hat:rhel_eus:9.4::appstreamkernel-zfcpdump-debuginfobefore 0:5.14.0-427.57.1.el9_40:5.14.0-427.57.1.el9_4

+56

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-2024-38385Jun 25, 2024 · genirq/irqdesc: Prevent use-after-free in irq_find_at_or_after()
    22Monitor
  • ← EarlierCVE-2024-38661Jun 25, 2024 · s390/ap: Fix crash in AP internal function modify_bitmap()
    22Monitor
  • Later →CVE-2024-39293Jun 25, 2024 · Revert "xsk: Support redirect to any socket bound to the same umem"
    18Monitor

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 Linux0c0b4a49d3e7f49690a6827a41faeffad5df7e21Vendor (CNA)
Linux Linux4.15Vendor (CNA)
Linux Linux4.19.316Vendor (CNA)
Linux Linux4.21Vendor (CNA)
Linux Linux681ff9a09accd8a4379f8bd30b7a1641ee19bb3eVendor (CNA)
Linux Linux76dc776153a47372719d664e0fc50d6355791abbVendor (CNA)
Linux Linux896a7e7d0d555ad8b2b46af0c2fa7de7467f9483Vendor (CNA)
Linux Linux9ad75e78747b5a50dc5a52f0f8e92e920a653f16Vendor (CNA)
Linux Linuxa95df6f04f2c37291adf26a74205cde0314d4577Vendor (CNA)
Linux Linuxb37c0edef4e66fb21a2fbc211471195a383e5ab8Vendor (CNA)
Linux Linuxe941b712e758f615d311946bf98216e79145ccd9Vendor (CNA)
debian:linux6.1.94-1 · Debian:12Package registry (OSV)
red hat:bpftool-debuginfo0:7.3.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-debuginfo0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-64k-debug-devel-matched0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-64k-debuginfo0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-64k-devel0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-64k-devel-matched0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-debug-debuginfo0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-debug-devel0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-debug-devel-matched0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-debuginfo0:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage registry (OSV)
red hat:kernel-debuginfo-common-aarch640:5.14.0-427.57.1.el9_4 · Red Hat:rhel_eus:9.4::appstreamPackage 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
none
Availability
none
Attack vector
Local
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
None
Availability impact
None

Weakness class (CWE)

—

CVSS vector

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

nvd-secondary

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