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CVE-2026-99287EUVD-2026-121531

xen-netback: Zero out sring pointers on unmap

Exploited
No known exploitation
Fix
No fix listed
Who is exposed
Not reported
Published
Last modified
Reference
Last checked
25/100 · provisional
None on Exploit-DB, Metasploit or GitHub

Summary

In the Linux kernel, the following vulnerability has been resolved:

xen-netback: Zero out sring pointers on unmap

If xenvif_map_frontend_data_rings() fails when a ring is already mapped, it unmaps them via xenvif_unmap_frontend_data_rings() which keeps the ring pointers unchanged. xenvif_connect_data()'s cleanup path calls xenvif_disconnect_queue() which in turn calls xenvif_unmap_frontend_data_rings() again, which will attempt to unmap the pointers a second time.

Show the full description

Zero out the ring pointers after they are unmapped to avoid this issue.

This is XSA-532

cve.now Index

25Pcve.now Index 25 of 100 · methodology v3 · provisional
  • Exploitation?/40Unknown. No CISA SSVC exploitation rating yet
  • Exposure?/25Unknown. No advisory context yet
  • Reach20/20Affects Linux kernel (software on nearly every server, desktop or phone)
  • Severity?/10Unknown. No CVSS score or vendor rating
  • No patch5/5No patch listed yet

What would change the score

  • Would score about 80 if added to CISA KEV
  • Would score about 75 if CISA's SSVC rates exploitation active
  • Would score about 47 if advisories confirm default setups are exposed

How the score works · Rankings

Check your systems with an agent

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Check whether my systems are affected by CVE-2026-99287 (xen-netback: Zero out sring pointers on unmap), using the cve.now data below.

Rules: work read-only. Do not run exploit code, proof-of-concept scripts or scanners that send attack payloads, and do not change any configuration, package, image or deployment. Report findings only.

What cve.now has for CVE-2026-99287 (entry last updated 2026-11-10):
Affected:
- Linux Linux: version range not reported
- Linux Linux: versions 5.5
Fixed versions: none listed yet.
Setup: unknown whether the bug needs a non-default feature or setting. Check the advisory.
CISA KEV: CVE-2026-99287 is not listed as of cve.now's last read.
This KEV status is for CVE-2026-99287 only. If you also check another CVE, look up its own KEV status; never assume it from this one.

How to check:
- Installed software: check what is actually running, not what a repo declares. Read the version from each host, container image and Kubernetes node (the binary's version output, the OS package database, image layers), and check whether the conditions above hold there. Distribution packages may carry a backported fix under an older version number; confirm against the distribution's own advisory.

Verify against the linked advisories before concluding, and cite the date you read each one:
- https://git.kernel.org/stable/c/87fd475dc4e354088f6534285388e7b061f54b35
- https://git.kernel.org/stable/c/c5f54af611ff6fe1d53fa05d8e87b469dc56122b
- https://git.kernel.org/stable/c/e7ba61734d6ad6adfd5bf617052e590743211669
- http://www.openwall.com/lists/oss-security/2026/11/10/26
- http://xenbits.xen.org/xsa/advisory-532.html
Do not conclude an asset is unaffected unless you checked it and the evidence covers both its version and the conditions above. If you could not check something, mark it unknown and say what is missing.

Report a table with one row per asset and these columns: Asset | Version or build | Status (affected, fixed, not applicable, unknown) | Compensating controls | Exposure (internet-facing, internal, none) | Evidence | Next action.

Entry: https://cve.now/CVE-2026-99287
For follow-up questions, use the cve.now MCP server at https://mcp.cve.now/mcp (no authentication), for example get_vulnerability with id CVE-2026-99287.

Timeline

  1. CVE published
  2. First seen by cve.now
  3. Record last updated

Affected versions

  • Linux Linux

    Version range not reported

  • Linux Linux

    5.5

Evidence 7

CVE record · 2

Establishes: The identifier and description.

  1. Record
  2. Record

Write-ups · 1

Establishes: Technical detail and context.

  1. Link

Other links · 4

  1. Link
  2. Link
  3. Link
  4. Link

Corrections

None so far.

Something wrong on this page? Report an error. Every fix is listed here.

Questions about CVE-2026-99287

Is CVE-2026-99287 being exploited?

It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data

Which versions are affected by CVE-2026-99287?

Linux: version 5.5.Source: cve.now feed data

Sources

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