CVE-2026-98975xfs: stop exchanging reflink flags when exchanging mappings
- 7.8HighCVSS base score
- 0.16%Exploitation in 30 daysEPSS · top 94% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: xfs: stop exchanging reflink flags when exchanging mappings When an exchange covers both files from offset 0 to i_disk_size, xmi_can_exchange_reflink_flags() assumes every mapping moved and hands the reflink flag over to the other file. That assumption is wrong. A file can still own shared blocks past i_disk_size, e.g. after EXCHANGE_RANGE_TO_EOF sets a smaller size without unmapping anything. The flag is cleared anyway, and the next write to such a block happens in place instead of CoW, corrupting the other file that shares it. Commit a23eca88448e ("xfs: fix exchange-range reflink flag clearing issue with INO1_WRITTEN") fixed one instance of this. Rather than add another special case, stop moving the flags. xfs_exchmaps_ensure_reflink() already sets the flag on both inodes before the exchange, so both just keep it. Nothing sets CLEAR_INO{1,2}_REFLINK anymore. Intents logged by older kernels may still carry them; recovery already masks them off, so they stay in the log format mask and are ignored. XFS_IOC_SWAPEXT has the same problem: it moves the reflink flag from one inode to the other along with the extents. Just removing that is not enough here: the exchange path flags both inodes up front in xfs_exchmaps_ensure_reflink(), but swapext has no such step, so the inode receiving the shared extents would be left without the flag. Set it on both inodes instead, and make sure both have a CoW fork, since an inode with the reflink flag is expected to have one. The flag now stays until FALLOC_FL_UNSHARE_RANGE, xfs_scrub, or a truncate to zero removes it.
Timeline
ID reserved
By Linux
- 28 days later
· 28 days later
Published
- 1 day later
· 1 day later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
| NVDNVD · Received | 3.1 | High7.8 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H |
- EPSS (exploitation in 30 days)
- 0.16% · top 94% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 7.8.
Affected products
- affected f0bc4d134b46607967bda1205ce3226a1bd95f42 – < 1fa2f3a7ef7ee0f2503a4b0afe24bc8c9d0820be
- affected f0bc4d134b46607967bda1205ce3226a1bd95f42 – < 7d3b9b2c9dc57f93f36c716ab752548cb4db9900
- affected f0bc4d134b46607967bda1205ce3226a1bd95f42 – < 4756c94260e69ce42612b8220c3614f02f7a11d5
- affected f0bc4d134b46607967bda1205ce3226a1bd95f42 – < d84d6c1a7f1e2de9e601703a326a4c1b7b421943
- affected 4.9
- unaffected < 4.9
- unaffected 6.12.114 – ≤ 6.12.*
- unaffected 6.18.57 – ≤ 6.18.*
- unaffected 7.2.11 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References4
- https://git.kernel.org/stable/c/1fa2f3a7ef7ee0f2503a4b0afe24bc8c9d0820be (opens in a new tab)
- https://git.kernel.org/stable/c/7d3b9b2c9dc57f93f36c716ab752548cb4db9900 (opens in a new tab)
- https://git.kernel.org/stable/c/4756c94260e69ce42612b8220c3614f02f7a11d5 (opens in a new tab)
- https://git.kernel.org/stable/c/d84d6c1a7f1e2de9e601703a326a4c1b7b421943 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- EUVD EUVD-2026-108769 (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://cveledger.app/cve/CVE-2026-98975)Record last updated .