CVE-2026-92487exfat: fix valid_size extension over a shared writable mapping
- —Not scoredno CVSS score yet
- 0.20%Exploitation in 30 daysEPSS · top 90% 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: exfat: fix valid_size extension over a shared writable mapping When a shared writable mapping has its valid_size extended by a buffered write or a page fault, exfat zeroes the page-cache gap below the new valid_size. A store through the mapping can race with this zeroing and be overwritten. Fix this by zeroing the gap lazily. Drop ->map_pages so that every first write fault goes through exfat_page_mkwrite(), which advances valid_size to cover the faulting page. With fault-around enabled, a store could install a writable PTE, skip ->page_mkwrite(), and land past valid_size without advancing it. Extending valid_size one faulting page at a time also leaves never-written pages in a large mapping alone. The gap is filled with block granularity, zeroing only the not-uptodate blocks and preserving blocks that may hold data stored through the mapping. On the buffered-write path the invalidate lock is held and the gap is unmapped before zeroing, so a racing store re-faults and, under the inode lock, completes only after the gap has been zeroed and valid_size covers it.
Timeline
ID reserved
By Linux
- 1 day later
· 1 day later
Published
- 32 days later
· 32 days 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
No CVSS score yet: neither the CNA, CISA nor NVD has scored this CVE. NVD status: Received.
- EPSS (exploitation in 30 days)
- 0.20% · top 90% of all CVEs (13 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
References
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-2026-82108 (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)
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[](https://cveledger.app/cve/CVE-2026-92487)Record last updated .