NVD / CVE Program· CNA Linux

CVE-2026-68167: btrfs: do not try compression for data reloc inodes

Noroxi assessment

Priority: Monitor (action score 0/100)

The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
Fixed version: Linux Linux 31a62e4ad66313cf1ebaa00c2a17d644a4b87d22, ae4316f332e03e628712e9dfb89f2b7d3c70c21a.
Mentioned 1 time in Turkish national cyber security advisories (siberguvenlik.gov.tr).

Low priority for now. Upgrade to Linux Linux 31a62e4ad66313cf1ebaa00c2a17d644a4b87d22, ae4316f332e03e628712e9dfb89f2b7d3c70c21a or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: btrfs: do not try compression for data reloc inodes [BUG] There is a syzbot report that the check inside get_new_location() triggered: BTRFS info (device loop0): found 31 extents, stage: move data extents BTRFS info (device loop0): leaf 8908800 gen 16 total ptrs 28 free space 1676 owner 18446744073709551607 item 0 key (256 INODE_ITEM 0) itemoff 3835 itemsize 160 inode generation 5 transid 0 size 0 nbytes 0 block group 0 mode 40755 links 1 uid 0 gid 0 rdev 0 sequence 0 flags 0x0 atime 1669132761.0 ctime 1669132761.0 mtime 1669132761.0 otime 0.0 item 1 key (256 INODE_REF 256) itemoff 3823 itemsize 12 index 0 name_len 2 item 2 key (258 INODE_ITEM 0) itemoff 3663 itemsize 160 inode generation 1 transid 16 size 733184 nbytes 106496 block group 0 mode 100600 links 0 uid 0 gid 0 rdev 0 sequence 24 flags 0x18 item 3 key (258 EXTENT_DATA 0) itemoff 3595 itemsize 68 generation 16 type 0 inline extent data size 47 ram_bytes 4096 compression 1 [...] item 27 key (18446744073709551611 ORPHAN_ITEM 258) itemoff 2376 itemsize 0 BTRFS error (device loop0): unexpected non-zero offset in file extent item for data reloc inode 258 key offset 0 offset 9277520992061368337 ------------[ cut here ]------------ btrfs_abort_should_print_stack(__error) [CAUSE] The above dump tree shows the first file extent item is inlined, which should make no sense for data reloc inodes, as such inodes just represent where the data extents are in the relocation destination chunk. However the relocation path preallocates space for each block, then dirties them, cluster by cluster. It's possible to have a single block at the beginning of the block group, and no other block in the same cluster. So relocation will preallocate a file extent for that block and dirty the first block. Then memory pressure forces the data reloc inode to be written back, before any other blocks are dirtied/allocated. Finally commit 3eaf5f082c4c ("btrfs: extract inlined creation into a dedicated delalloc helper") changed the sequence of delalloc. Before that commit we always tried NOCOW first, so that dirtied block would be written back into the preallocated space, and appear as a regular extent. But with that commit, we always try inline first, and since compression is forced, we try compressing the first block, and then inline the compressed data, resulting in the above inlined file extent in the data reloc tree. Then the check in get_new_location() will check the file offset, without checking if the file extent is inlined or not, resulting in the above failure. [FIX] Do not allow compression for data reloc inodes. Since data reloc inode sizes are always block aligned, as long as we do not compress, @data_len will always be at least one block, and that will cause can_cow_file_range_inline() to return false, thus no inlined extent will be created.

—No exploit Fix available

Published: Aug 10, 2026
Updated: Aug 17, 2026
EPSS: 0.1% · 9th percentile
CWE: —

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Action score

Monitor

Low priority for now.

CVSS: 0 / 40 · —
CISA KEV: 0 / 30 · Not listed
EPSS: 0 / 30 · 0.1%

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Noroxi analysis

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Affected systems

Is your version affected?

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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
- 7.1affected
- 3eaf5f082c4cc71dea70bee23355bf63b24df303 and later · before 31a62e4ad66313cf1ebaa00c2a17d644a4b87d22affected · git
- 3eaf5f082c4cc71dea70bee23355bf63b24df303 and later · before ae4316f332e03e628712e9dfb89f2b7d3c70c21aaffected · git
- before 7.1not affected · semver
- 7.1.6 and later · up to and including 7.1.*not affected · semver
- 7.2 and laternot affected · original_commit_for_fix

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

Ecosystem	Package	Affected range	Fix
Debian:14	linux	before 7.1.6-1	7.1.6-1

Same product

linux: all records

Other highest-scoring records for the same primary product.

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Published before and after this one in the same product

← EarlierCVE-2026-68165Aug 10, 2026 · mm/damon/core: validate ranges in damon_set_regions()
0Monitor
← EarlierCVE-2026-68166Aug 10, 2026 · userfaultfd: prevent registration of special VMAs
0Monitor
Later →CVE-2026-68168Aug 10, 2026 · afs: Fix afs_edit_dir_remove() to get, not find, block 0
0Monitor

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	31a62e4ad66313cf1ebaa00c2a17d644a4b87d22	Vendor (CNA)
Linux Linux	ae4316f332e03e628712e9dfb89f2b7d3c70c21a	Vendor (CNA)
debian:linux	7.1.6-1 · Debian:14	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

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No dated events beyond publication.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

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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).