ntfs: set dummy blocksize to read boot_block when mounting
In the Linux kernel, the following vulnerability has been resolved: ntfs: set dummy blocksize to read boot_block when mounting When mounting, sb->s_blocksize is used to read the boot_block without being defined or validated. Set a dummy blocksize before attempting to read the boot_block. The issue can be triggered with the following syz reproducer: mkdirat(0xffffffffffffff9c, &(0x7f0000000080)='./file1\x00', 0x0) r4 = openat$nullb(0xffffffffffffff9c, &(0x7f0000000040), 0x121403, 0x0) ioctl$FS_IOC_SETFLAGS(r4, 0x40081271, &(0x7f0000000980)=0x4000) mount(&(0x7f0000000140)=@nullb, &(0x7f0000000040)='./cgroup\x00', &(0x7f0000000000)='ntfs3\x00', 0x2208004, 0x0) syz_clone(0x88200200, 0x0, 0x0, 0x0, 0x0, 0x0) Here, the ioctl sets the bdev block size to 16384. During mount, get_tree_bdev_flags() calls sb_set_blocksize(sb, block_size(bdev)), but since block_size(bdev) > PAGE_SIZE, sb_set_blocksize() leaves sb->s_blocksize at zero. Later, ntfs_init_from_boot() attempts to read the boot_block while sb->s_blocksize is still zero, which triggers the bug. [almaz.alexandrovich@paragon-software.com: changed comment style, added return value handling]
- Published
- Jan 13, 2026
- Updated
- Jun 17, 2026
- EPSS
- 0.2% · 8th percentile
- CWE
- —
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Report tools
Action score
0
Monitor
Low priority for now.
- CVSS
- 0 / 40 · —
- CISA KEV
- 0 / 30 · Not listed
- EPSS
- 0 / 30 · 0.2%
Affected systems
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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
- 5.15affected
- 28861e3bbd9e7ac4cd9c811aad71b4d116e27930 and later · before 0c9327c8abf9c8f046e45008bb43d94d8ee5c6c5affected · git
- 28861e3bbd9e7ac4cd9c811aad71b4d116e27930 and later · before 44a38eb4f7876513db5a1bccde74de9bc4389d43affected · git
- 28861e3bbd9e7ac4cd9c811aad71b4d116e27930 and later · before 4fff9a625da958a33191c8553a03283786f9f417affected · git
- 28861e3bbd9e7ac4cd9c811aad71b4d116e27930 and later · before b3c151fe8f543f1a0b8b5df16ce5d97afa5ec85aaffected · git
- 28861e3bbd9e7ac4cd9c811aad71b4d116e27930 and later · before d1693a7d5a38acf6424235a6070bcf5b186a360daffected · git
- before 5.15not affected · semver
- 6.1.167 and later · up to and including 6.1.*not affected · semver
- 6.6.120 and later · up to and including 6.6.*not affected · semver
- 6.12.64 and later · up to and including 6.12.*not affected · semver
Package-level exposure
OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.
| Ecosystem | Package | Affected range | Fix |
|---|---|---|---|
| Debian:12 | linux | before 6.1.170-1 | 6.1.170-1 |
| Debian:13 | linux | before 6.12.69-1 | 6.12.69-1 |
| Debian:14 | linux | before 6.18.3-1 | 6.18.3-1 |
Same product
linux: all recordsOther highest-scoring records for the same primary product.
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Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
| Product / package | Fixed version | Source |
|---|---|---|
| Linux Linux | 0c9327c8abf9c8f046e45008bb43d94d8ee5c6c5 | Vendor (CNA) |
| Linux Linux | 44a38eb4f7876513db5a1bccde74de9bc4389d43 | Vendor (CNA) |
| Linux Linux | 4fff9a625da958a33191c8553a03283786f9f417 | Vendor (CNA) |
| Linux Linux | b3c151fe8f543f1a0b8b5df16ce5d97afa5ec85a | Vendor (CNA) |
| Linux Linux | d1693a7d5a38acf6424235a6070bcf5b186a360d | Vendor (CNA) |
| azl3 kernel 6.6.119.3-3 on Azure Linux 3.0 | 6.6.121.1-1 · CBL-Mariner Releases | Microsoft (MSRC) |
| debian:linux | 6.1.170-1 · Debian:12 | Package 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.
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
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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.
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Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
No CVSS vector for this record, so attack conditions can't be derived.
Weakness class (CWE)
—
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
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Noroxi analysis
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References
- git.kernel.org/stable/c/0c9327c8abf9c8f046e45008bb43d94d8ee5c6c5
- git.kernel.org/stable/c/44a38eb4f7876513db5a1bccde74de9bc4389d43
- git.kernel.org/stable/c/4fff9a625da958a33191c8553a03283786f9f417
- git.kernel.org/stable/c/b3c151fe8f543f1a0b8b5df16ce5d97afa5ec85a
- git.kernel.org/stable/c/d1693a7d5a38acf6424235a6070bcf5b186a360d
Vendor advisories and official records. Exploit/PoC links are deliberately left out.