How severe is CVE-2026-43066?

CVE-2026-43066 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-43066 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-43066?

CVE-2026-43066 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2026-43066?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

Does CVE-2026-43066 have an EU (EUVD) identifier?

Yes. CVE-2026-43066 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27365.

When was CVE-2026-43066 published?

CVE-2026-43066 was published on 2026-05-05 and last updated on 2026-06-17.

CVE-2026-43066

CVE-2026-43066 is a medium-severity vulnerability in Linux Linux Kernel with a CVSS 3.x base score of 5.5. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-401.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
EPSS exploit prediction: 0% (2nd percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-27365
Weakness: CWE-401
Affected product: Linux Linux Kernel
Published: 2026-05-05
Last modified: 2026-06-17

Description

In the Linux kernel, the following vulnerability has been resolved: ext4: fix iloc.bh leak in ext4_fc_replay_inode() error paths During code review, Joseph found that ext4_fc_replay_inode() calls ext4_get_fc_inode_loc() to get the inode location, which holds a reference to iloc.bh that must be released via brelse(). However, several error paths jump to the 'out' label without releasing iloc.bh: - ext4_handle_dirty_metadata() failure - sync_dirty_buffer() failure - ext4_mark_inode_used() failure - ext4_iget() failure Fix this by introducing an 'out_brelse' label placed just before the existing 'out' label to ensure iloc.bh is always released. Additionally, make ext4_fc_replay_inode() propagate errors properly instead of always returning 0.

Frequently asked questions

What is CVE-2026-43066?: In the Linux kernel, the following vulnerability has been resolved: ext4: fix iloc.bh leak in ext4_fc_replay_inode() error paths During code review, Joseph found that ext4_fc_replay_inode() calls ext4_get_fc_inode_loc() to get the inode location, which holds a reference to iloc.bh that must be released via brelse(). However, several error paths jump to the 'out' label without releasing iloc.bh: - ext4_handle_dirty_metadata() failure - sync_dirty_buffer() failure - ext4_mark_inode_used() failure - ext4_iget() failure Fix this by introducing an 'out_brelse' label placed just before the existing 'out' label to ensure iloc.bh is always released. Additionally, make ext4_fc_replay_inode() propagate errors properly instead of always returning 0.
How severe is CVE-2026-43066?: CVE-2026-43066 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires low privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-43066 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (2nd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-43066?: CVE-2026-43066 primarily affects Linux Linux Kernel. In total, 6 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2026-43066?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-43066 have an EU (EUVD) identifier?: Yes. CVE-2026-43066 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-27365.
When was CVE-2026-43066 published?: CVE-2026-43066 was published on 2026-05-05 and last updated on 2026-06-17.

References

Affected products (6)

cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc1:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc2:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc3:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc4:*:*:*:*:*:*
cpe:2.3:o:linux:linux_kernel:7.0:rc5:*:*:*:*:*:*

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