CVE-2026-80869

Description

In the Linux kernel, the following vulnerability has been resolved: ntfs: bound the attribute-list entry in ntfs_read_inode_mount() The $MFT attribute-list walk in ntfs_read_inode_mount() validates each entry only with "(u8 *)al_entry + 6 > al_end" and "(u8 *)al_entry + le16_to_cpu(al_entry->length) > al_end", but then reads al_entry->lowest_vcn (an __le64 at offset 8) and al_entry->mft_reference (offset 16) -- fields beyond the 6 bytes proven in range. al_entry->length is attacker-controlled and only required non-zero, so a short entry (e.g. length 8) placed at the tail passes both checks while the lowest_vcn / mft_reference reads fall past al_end. al_end is ni->attr_list + attr_list_size (the on-disk size); the buffer is kvzalloc(round_up(attr_list_size, SECTOR_SIZE)), so the sector rounding usually absorbs the over-read -- but when attr_list_size is a multiple of SECTOR_SIZE there is no slack and a crafted $MFT attribute list produces an out-of-bounds read at mount time. Validate the entry with ntfs_attr_list_entry_is_valid() (added in patch 1/3) before dereferencing it, matching the bound the other attribute-list walks now use. The validator already requires the length to cover the fixed header, which makes the separate "!al_entry->length" check redundant, so drop it too.

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EPSS — Exploit Prediction

0.0015

Probability of exploitation

0.04%

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/98634df5b1cb56c26299b7409227025ddb0167d8 https://git.kernel.org/stable/c/c7a7e48e71ce915ec4cbd6e9f355590c1ecbc29a

Frequently Asked Questions

What is CVE-2026-80869? +

In the Linux kernel, the following vulnerability has been resolved: ntfs: bound the attribute-list entry in ntfs_read_inode_mount() The $MFT attribute-list walk in ntfs_read_inode_mount() validates each entry only with "(u8 *)al_entry + 6 > al_end" and "(u8 *)al_entry + le16_to_cpu(al_entry->length) > al_end", but then reads al_entry->lowest_vcn (an __le64 at offset 8) and al_entry->mft_reference (offset 16) -- fields beyond the 6 bytes proven in range. al_entry->length is attacker-controlled and only required non-zero, so a short entry (e.g. length 8) placed at the tail passes both checks while the lowest_vcn / mft_reference reads fall past al_end. al_end is ni->attr_list + attr_list_size (the on-disk size); the buffer is kvzalloc(round_up(attr_list_size, SECTOR_SIZE)), so the sector rounding usually absorbs the over-read -- but when attr_list_size is a multiple of SECTOR_SIZE there is no slack and a crafted $MFT attribute list produces an out-of-bounds read at mount time. Validate the entry with ntfs_attr_list_entry_is_valid() (added in patch 1/3) before dereferencing it, matching the bound the other attribute-list walks now use. The validator already requires the length to cover the fixed header, which makes the separate "!al_entry->length" check redundant, so drop it too.

How do I check if I'm vulnerable to CVE-2026-80869? +

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.