CVE Intelligence
Unknown

CVE-2026-90391 — lib/test_hmm: fail dmirror_fault() when the mirrored mm is gone

In the Linux kernel, the following vulnerability has been resolved: lib/test_hmm: fail dmirror_fault() when the mirrored mm is gone dmirror_fault() is called from the dmirror_read() and dmirror_write() retry loops after dmirror_do_read() or dmirror_do_write() finds a missing device page table entry. If the mirrored mm has already exited, mmget_not_zero() fails. The current code returns 0 in that case, which tells the caller that faulting succeeded even though no page was faulted and no device page table entry was installed. The caller then retries the same address, hits -ENOENT again, and can loop forever without making progress. Return -EFAULT instead, so the ioctl fails when the mirrored mm is no longer faultable.

Published Sep 17, 2026 · Updated Oct 15, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: Linux

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.
How the score was calculated
  • EPSS 0.2% (30-day exploitation probability)+2

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation
Not confirmed
Not in CISA KEV — an absence of record, not proof it is unexploited.
EPSS FIRST
0.21%
ahead of 11% of scored CVEs · Oct 16, 2026
Affects
Linux
Linux
CVSS base
—
Score not published yet.

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

No fix documented by the sources we poll. That does not mean none exists: check the vendor advisory.

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

  1. Identify exposed assets running the affected vendor/product/version combinations (Linux Linux).
  2. No fix documented in the sources: reduce exposure and monitor the vendor advisory.
  3. Search available logs for exploit probes, errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

VendorProductVersionsStatusSource
Linux Linux ≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < 50606ced303782f8715e2d0b98ca374ea498fa29≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < 541a67f21ab807c8dbc0ea88d5a2eb73b2618090≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < d8e64ffab01e032ae29159d27230ace8cf8bdc80≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < 2636569ea7c19d9a40db4a1e8d0a027bdacf1569≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < 701347e31aa607f3782403151a3125729d685275≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < af7a6d6ec36a16a583ba2e4e9984c3cf1fe34655≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < a2074f86fc9653831e4fb7b711bb715db330f182≥ b2ef9f5a5cb37643ca5def3516c546457074b882 and < 6a8024511ddf4877435c34fb3d6028aa8e590649
and 1 more version 5.8
Vulnerable CVE Program (cve.org) e CISA ADP

EPSS over time FIRST

Oct 15, 2026 → Oct 16, 2026 · 2 reading(s) · max 0.21%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

  • Not enough vector or weakness data: use the affected application’s logs as a starting point.
application logs

Timeline

What happened to this CVE, newest first.

  • 2026
  • Record published
    Oct 15, 2026
  • Affected products added · linux/linux
    Oct 15, 2026 · CVE Program (cve.org) e CISA ADP
  • Source status changed · → Received
    Oct 15, 2026 · NIST National Vulnerability Database
  • Record created in this database
    Oct 15, 2026 · NIST National Vulnerability Database
  • CVE published
    Sep 17, 2026 · Linux

Source activity

Repeated readings are counted rather than listed.

  • 1× Official description updated · Oct 15, 2026 – Oct 15, 2026

References

8 on the record

Elsewhere on this site

Linux
every CVE for this vendor

Related CVEs (same products)

  • CVE-2026-98866 sched/cache: Introduce task_struct->sched_cache_grp to fix UAF 9h
  • CVE-2026-98867 dm-pcache: bound the logical key offset from persistent memory 9h
  • CVE-2026-98868 dm-pcache: reject a kset that overruns its segment 9h
  • CVE-2026-98856 kprobes: Skip disarmed probes when checking optkprobe overlap 9h
  • CVE-2026-98857 ipvs: bound LBLCR and LBLC cache growth 9h
  • CVE-2026-98858 io_uring: fix task_work add use-after-free with SQPOLL 9h

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

  • No CVSS score published by NVD, the CNA, CISA or GitHub so far.
  • No fixed version, patch or mitigation documented.
  • No CISA SSVC assessment.
  • No CWE classification.
  • No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
  • No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
  • No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-90391 is "lib/test_hmm: fail dmirror_fault() when the mirrored mm is gone", rated Unknown. It affects Linux (Linux); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. EPSS 0.21% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

Comments

Moderated technical discussion. Read the community guidelines.

No comments yet.

Sign in or create an account to comment and suggest corrections.