CVE-2026-89611 (CVSS 9.8)

Description

In the Linux kernel, the following vulnerability has been resolved: ntfs: validate non-resident attribute offsets ntfs_attr_update_meta() shifts the attribute name when converting between non-sparse and sparse attributes. Converting to sparse also adds the compressed_size field before the name and mapping pairs, requiring eight additional bytes in the attribute record. However, the validator does not check that name_offset is within safe boundaries for these operations or that the additional space is available. A malicious MFT record could set name_offset such that: 1. The name is positioned at the very end of a non-sparse attribute. Converting to sparse would shift the name forward by 8 bytes, writing beyond the attribute boundary. 2. The name overlaps with the mapping pairs, causing corruption during conversion. Add validation to ensure: - For named attributes, name_offset is within valid bounds - Name does not extend beyond the attribute or overlap with mapping pairs - For non-sparse, non-compressed attributes, eight bytes are available after mapping_pairs_offset for the compressed_size field The space check also covers unnamed attributes, for which name_offset = 0 is valid and no name range needs to be checked.

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CVSS v3.1 Score

9.8

CRITICAL

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

EPSS — Exploit Prediction

0.0038

Probability of exploitation

0.32%

Percentile rank

EPSS estimates the probability that this vulnerability will be exploited in the wild within the next 30 days. A higher score means more likely to be exploited.

References

Other References

https://git.kernel.org/stable/c/a83e82b0ec3ae523028e24813f23f18b43e8fc1c https://git.kernel.org/stable/c/cd7b3dc7557faadeea626034e3bac68a449851ef

Frequently Asked Questions

What is CVE-2026-89611? +

In the Linux kernel, the following vulnerability has been resolved: ntfs: validate non-resident attribute offsets ntfs_attr_update_meta() shifts the attribute name when converting between non-sparse and sparse attributes. Converting to sparse also adds the compressed_size field before the name and mapping pairs, requiring eight additional bytes in the attribute record. However, the validator does not check that name_offset is within safe boundaries for these operations or that the additional space is available. A malicious MFT record could set name_offset such that: 1. The name is positioned at the very end of a non-sparse attribute. Converting to sparse would shift the name forward by 8 bytes, writing beyond the attribute boundary. 2. The name overlaps with the mapping pairs, causing corruption during conversion. Add validation to ensure: - For named attributes, name_offset is within valid bounds - Name does not extend beyond the attribute or overlap with mapping pairs - For non-sparse, non-compressed attributes, eight bytes are available after mapping_pairs_offset for the compressed_size field The space check also covers unnamed attributes, for which name_offset = 0 is valid and no name range needs to be checked. It has a CVSS v3.1 base score of 9.8 (CRITICAL).

How severe is CVE-2026-89611? +

CVE-2026-89611 has a CVSS v3.1 score of 9.8 out of 10, rated CRITICAL. This is a critical vulnerability that should be patched immediately. The EPSS score is 0.0038, placing it in the 0th percentile for exploitation probability.

How do I check if I'm vulnerable to CVE-2026-89611? +

You can use Secably's free Website Scanner to check your website for known vulnerabilities. For infrastructure scanning, use the Port Scanner to identify exposed services that may be affected. Check the vendor advisories linked above for specific patch and version information.

CVE-2026-89611