CVE-2026-99274smb: client: fix fiemap wild read on empty truncated response
- —Not scoredno CVSS score yet
- 0.16%Exploitation in 30 daysEPSS · top 95% 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: smb: client: fix fiemap wild read on empty truncated response smb3_fiemap() treats -E2BIG from SMB2_ioctl() as a truncated range blob and loops for the next chunk. If the server reports STATUS_BUFFER_OVERFLOW with OutputCount == 0, SMB2_ioctl() returns -E2BIG with out_data == NULL and out_data_len == 0, and the existing length checks accept the empty result. The loop then evaluates next = out_data[num - 1].file_offset + ... with num == 0, reading 16 bytes before NULL. Reject a truncated range blob that contains no range, so the resume offset is never computed from an empty response. Also require the last range in a truncated blob to advance the resume offset without overflowing, and to stay within the requested range; a malicious or broken server could otherwise make no progress or underflow len and loop forever. Free the previous response buffer before retrying. Reproduced on 6.6.87.2 with a malicious SMB2 server that answers FSCTL_QUERY_ALLOCATED_RANGES with STATUS_BUFFER_OVERFLOW and OutputCount == 0; an FS_IOC_FIEMAP ioctl on the mount oopses in cifs_fiemap() with CR2 = fffffffffffffff8. The code path is unchanged on mainline.
Timeline
ID reserved
By Linux
- 43 days later
· 43 days later
Published
- 3 days later
· 3 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)
- 0.16% · top 95% of all CVEs (14 Nov 2026)
The list uses the assigner's score when there is one, then CISA's, then NVD's: Not scored.
Affected products
- affected 2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4 – < 8e0d425b808c367f5033eb72aa4528ae18473627
- affected 2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4 – < 4a426ca5be7e3dedbe76575b967db04fbf01136f
- affected 2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4 – < 31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca
- affected 2f3ebaba13cebd8badfb9aed31c0cf3cc82eb4f4 – < f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc
- affected 5.2
- unaffected < 5.2
- unaffected 6.12.117 – ≤ 6.12.*
- unaffected 6.18.61 – ≤ 6.18.*
- unaffected 7.3.2 – ≤ 7.3.*
- unaffected 7.4-rc1 – ≤ *
References
References4
- https://git.kernel.org/stable/c/8e0d425b808c367f5033eb72aa4528ae18473627 (opens in a new tab)
- https://git.kernel.org/stable/c/4a426ca5be7e3dedbe76575b967db04fbf01136f (opens in a new tab)
- https://git.kernel.org/stable/c/31f6dbb29fe17fa9595c7e8b19fd92915b03a4ca (opens in a new tab)
- https://git.kernel.org/stable/c/f5baa17a0f316c235d61623ac8e8fb32c2b3c0cc (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-2026-119288 (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-2026-99274)Record last updated .