CVE-2026-99155scsi: xen/scsifront: Check for a NULL shadow entry on a backend response
- —Not scoredno CVSS score yet
- 0.19%Exploitation in 30 daysEPSS · top 92% 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: scsi: xen/scsifront: Check for a NULL shadow entry on a backend response scsifront_do_response() validates the rqid in a backend response against VSCSIIF_MAX_REQS before using it to index info->shadow[], but then dereferences the entry to test ->inflight without checking that the slot is populated. Shadow slots are NULL before a command is submitted (the host private area is zeroed at allocation) and are reset to NULL in _scsifront_put_rqid() once a request completes, so an in-range rqid that does not correspond to an outstanding request makes the frontend dereference a NULL pointer. A malicious or buggy backend can thus crash the guest by returning a response whose rqid is in range but not in flight -- for example a spurious response before any command has been issued, or a duplicate of one already completed. The ring has only VSCSIIF_MAX_REQS (16) slots, so before the first command every in-range rqid selects a NULL slot. Reject a response whose shadow slot is not populated.
Timeline
ID reserved
By Linux
- 33 days later
· 33 days later
Published
- 2 days later
· 2 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)
- 0.19% · top 92% 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 6d1c2f48f3fcf5f42967938c8ba6b42ac6b44b43 – < 448b9a8b530b753d346dab10add09a502fc719a4
- affected 6d1c2f48f3fcf5f42967938c8ba6b42ac6b44b43 – < e397d4da76bed72db6ac4a0848fb6217f8394dca
- affected 6d1c2f48f3fcf5f42967938c8ba6b42ac6b44b43 – < 90186a2354821329a27d92b266c0f05e8f4f637c
- affected 6d1c2f48f3fcf5f42967938c8ba6b42ac6b44b43 – < 1d91ec793d6c80eca963d426e0da832d40a062df
- affected 6d1c2f48f3fcf5f42967938c8ba6b42ac6b44b43 – < 15791e57f57f7050014d08cfe239d4aa1e6b94b0
- affected 6d1c2f48f3fcf5f42967938c8ba6b42ac6b44b43 – < 8c8222c255772713eb36cde695777a1fce224917
- affected 5.19
- unaffected < 5.19
- unaffected 6.1.191 – ≤ 6.1.*
- unaffected 6.6.161 – ≤ 6.6.*
- unaffected 6.12.115 – ≤ 6.12.*
- unaffected 6.18.59 – ≤ 6.18.*
- unaffected 7.2.13 – ≤ 7.2.*
- unaffected 7.3 – ≤ *
References
References6
- https://git.kernel.org/stable/c/448b9a8b530b753d346dab10add09a502fc719a4 (opens in a new tab)
- https://git.kernel.org/stable/c/e397d4da76bed72db6ac4a0848fb6217f8394dca (opens in a new tab)
- https://git.kernel.org/stable/c/90186a2354821329a27d92b266c0f05e8f4f637c (opens in a new tab)
- https://git.kernel.org/stable/c/1d91ec793d6c80eca963d426e0da832d40a062df (opens in a new tab)
- https://git.kernel.org/stable/c/15791e57f57f7050014d08cfe239d4aa1e6b94b0 (opens in a new tab)
- https://git.kernel.org/stable/c/8c8222c255772713eb36cde695777a1fce224917 (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-2026-111907 (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-2026-99155)Record last updated .