How severe is CVE-2026-55392?

CVE-2026-55392 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2026-55392 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.

How do I fix CVE-2026-55392?

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

Does CVE-2026-55392 have an EU (EUVD) identifier?

Yes. CVE-2026-55392 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37927.

When was CVE-2026-55392 published?

CVE-2026-55392 was published on 2026-06-18 and last updated on 2026-06-23.

CVE-2026-55392

CVE-2026-55392 is a medium-severity vulnerability 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-1284.

Key facts

Severity: Medium (CVSS 3.x base score 5.5)
CVSS v4: 6.7
EPSS exploit prediction: 0% (1st percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-37927
Weakness: CWE-1284
Published: 2026-06-18
Last modified: 2026-06-23

Description

NILFS utilities through 2.3.0, fixed in commit 26efb5d, nilfs_sb_is_valid() function fails to validate s_log_block_size field in NILFS2 superblock before bit-shift operations. Attackers supplying crafted NILFS2 images trigger undefined behavior through oversized shifts or out-of-memory conditions, crashing tools like nilfs-tune and dumpseg.

Frequently asked questions

What is CVE-2026-55392?: NILFS utilities through 2.3.0, fixed in commit 26efb5d, nilfs_sb_is_valid() function fails to validate s_log_block_size field in NILFS2 superblock before bit-shift operations. Attackers supplying crafted NILFS2 images trigger undefined behavior through oversized shifts or out-of-memory conditions, crashing tools like nilfs-tune and dumpseg.
How severe is CVE-2026-55392?: CVE-2026-55392 has a CVSS 3.x base score of 5.5, rated medium severity. It is exploitable over local access with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2026-55392 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (1st percentile), an estimate of the probability of exploitation in the next 30 days.
How do I fix CVE-2026-55392?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
Does CVE-2026-55392 have an EU (EUVD) identifier?: Yes. CVE-2026-55392 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-37927.
When was CVE-2026-55392 published?: CVE-2026-55392 was published on 2026-06-18 and last updated on 2026-06-23.

References

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