CVE-2026-93834

Qemu-kvm: 9pfs: use-after-free race in tlcreate/twalk allows vm guest escape

Products / packages Red Hat Enterprise Linux 10 · Red Hat Enterprise Linux 6 · Red Hat Enterprise Linux 7 · 6 more

Published 25/09/2026, 13:36:17 UTC

Severity and exploitation

Not in CISA KEV

KEV coverage does not rule out exploitation.

KEV checked 14/11/2026, 22:00:33 UTC

redhat · CVSS:3.1 · 8.8

Assessment vector

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Severity

high8.8

CVSS measures technical severity, not the likelihood of an attack.

Known exploitation

Not listed in the checked CISA KEV catalog

Absence from CISA KEV does not rule out attacks.

Public exploit

Exploit reference published

Source-linked evidence; not proof of attacks in the wild or independent validation.

Remediation

Source guidance available

Review the recorded instructions. Guidance may be a workaround rather than a fixed version.

What this means

A use-after-free vulnerability in QEMU's 9pfs subsystem allows a malicious guest user to escape the shared directory boundary, potentially leading to arbitrary host file read/write. The vulnerability is due to a race condition between the main thread and a worker thread when processing concurrent Tlcreate and Twalk requests. Affected products include Red Hat Enterprise Linux 8, 9, and 10.

Summarized by @cf/meta/llama-3.3-70b-instruct-fp8-fast. Verify details against the original sources.

Attack conditions

No attack-condition excerpt has been identified here. Review the full source description and references for authentication, network access, and configuration requirements.

Review supporting sources →

Affected versions

Check the exact model, release, and any platform requirements against your installation.

Red Hat · redhat

Red Hat Enterprise Linux 10

0 ranges

redhat version evidence

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Other versions: affected

Product identifiers (CPE)

cpe:/a:redhat:enterprise_linux:10

Red Hat · redhat

Red Hat Enterprise Linux 6

0 ranges

redhat version evidence

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Other versions: unaffected

Product identifiers (CPE)

cpe:/o:redhat:rhel_els:6

Red Hat · redhat

Red Hat Enterprise Linux 7

0 ranges

redhat version evidence

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Other versions: unaffected

Product identifiers (CPE)

cpe:/o:redhat:rhel_els:7

Red Hat · redhat

Red Hat Enterprise Linux 7

0 ranges

redhat version evidence

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Other versions: unaffected

Product identifiers (CPE)

cpe:/o:redhat:rhel_els:7

Red Hat · redhat

Red Hat Enterprise Linux 8

0 ranges

redhat version evidence

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Other versions: affected

Product identifiers (CPE)

cpe:/a:redhat:enterprise_linux:8

Red Hat · redhat

Red Hat Enterprise Linux 8

0 ranges

redhat version evidence

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Other versions: affected

Product identifiers (CPE)

cpe:/a:redhat:enterprise_linux:8

Red Hat · redhat

Red Hat Enterprise Linux 9

0 ranges

redhat version evidence

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Other versions: affected

Product identifiers (CPE)

cpe:/a:redhat:enterprise_linux:9

Red Hat · redhat

Red Hat Enterprise Linux for NVIDIA 26

0 ranges

redhat version evidence

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Other versions: unknown

Product identifiers (CPE)

cpe:/a:redhat:enterprise_linux_nvidia:

Red Hat · redhat

Red Hat OpenShift Container Platform 4

0 ranges

redhat version evidence

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Other versions: affected

Product identifiers (CPE)

cpe:/a:redhat:openshift:4

Red Hat · redhat

Red Hat OpenShift Container Platform 4

0 ranges

redhat version evidence

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Other versions: affected

Product identifiers (CPE)

cpe:/a:redhat:openshift:4

Red Hat · redhat

Red Hat OpenShift Container Platform 5

0 ranges

redhat version evidence

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Other versions: affected

Product identifiers (CPE)

cpe:/a:redhat:openshift:5

Red Hat · redhat

Red Hat OpenStack Platform 13 (Queens)

0 ranges

redhat version evidence

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Other versions: unaffected

Product identifiers (CPE)

cpe:/a:redhat:openstack:13

Automatic dependency matching is unavailable for this record. Use the product evidence and publisher’s instructions to check your installation.

What to do

Compare your installed product and version with the affected versions above. A matching product name alone does not confirm exposure.

Do not configure 9pfs/VirtFS filesystem sharing (-fsdev, -virtfs) on affected QEMU instances. If host-guest file sharing is required, use virtio-fs (virtiofsd) as an alternative, which does not use the vulnerable 9pfs code path.

redhat guidance ↗

cve.new guidance unless attributed to a publisher. This page does not inspect your installation.

Public exploit evidence

The sources identify public exploit references. We have not independently tested them; their availability does not establish exploitation in the wild.

gitlab.com/qemu-project/qemu/-/work_items/4491 ↗Attributed to CISA-ADP

Original source description

Read the full publisher description

A use-after-free vulnerability was found in QEMU's 9pfs subsystem. A race condition between the main thread and a worker thread when processing concurrent Tlcreate and Twalk requests allows a malicious guest user to craft a fid path containing stale heap data, bypassing directory traversal restrictions and escaping the shared directory boundary. This can lead to arbitrary host file read/write and code execution (VM escape) as the QEMU process user.

References

3 sources

access.redhat.com/security/cve/CVE-2026-93834

Security advisoryredhat

bugzilla.redhat.com/show_bug.cgi

Source referenceredhat

gitlab.com/qemu-project/qemu/-/work_items/4491

Public exploit referenceredhat · CISA-ADP

Inside the record

Evidence available

Package identity · not supplied

Version evidence · not supplied

Remediation guidance

Weakness classification

Additional publishers

Describes the evidence in this view, not whether the product is safe.

Original records

CVE-2026-93834

View the latest unmodified CVE JSON from the official source. It may be newer than this imported page.

cve.new JSON →

Underlying weaknesses

The source’s classification of what caused the vulnerability.

CWE-416 ↗

Use After Free

redhat

Contributing organizations · 2

redhat

Assigning organization

2026-11-05

CISA-ADP

Additional data publisher

2026-09-25

Timeline

All times UTC

25 Sept 2026, 13:36
Advisory published
Publication date supplied by the source.
5 Nov 2026, 00:12
Source updated
Latest modification date supplied by the source.
5 Nov 2026, 06:57
Last imported by cve.new
Latest catalog import, not the date we first saw this advisory.

What changed

Follow changes

CVE · CVE-2026-938342026-11-05

Observed 2026-11-05T06:57:13.844Z · upstream updated 2026-11-05T00:12:18.099Z

Product or version evidence changed

before

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  },
  {
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    "platforms": [],
    "versions": [],
    "defaultStatus": "affected",
    "cpes": [
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  },
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    "name": "Red Hat OpenStack Platform 13 (Queens)",
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  }
]

after

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    "name": "Red Hat Enterprise Linux 10",
    "platforms": [],
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  },
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    "vendor": "Red Hat",
    "name": "Red Hat Enterprise Linux 6",
    "platforms": [],
    "versions": [],
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  },
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    "vendor": "Red Hat",
    "name": "Red Hat Enterprise Linux 7",
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    "versions": [],
    "defaultStatus": "unaffected",
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      "cpe:/o:redhat:rhel_els:7"
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  },
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    "vendor": "Red Hat",
    "name": "Red Hat Enterprise Linux 8",
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  },
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  }
]

Large field values are marked as truncated previews. Original source snapshots remain retained.

Showing up to 50 most recent observed changes.

Reading the signals

Severity · CVSS: Technical impact and attack conditions. The headline is the highest imported catalog score; sources may disagree.
Observed exploitation · KEV: An absent or unavailable KEV listing does not establish that exploitation has not occurred.
Predicted exploitation · EPSS: 0.40% estimated probability in the next 30 days. 2026-10-30 · FIRST EPSS.

CISA-ADP · SSVC

CISA Coordinator · 2026-09-25

Exploitation: poc
Automatable: no
Technical Impact: total

SSVC describes the publisher’s decision context. Your organization’s exposure and priorities may differ.

Record identifiers

Aliases: None recorded

Source evidence

Request a correction or dispute

Start with the assigning organization for this record. Include the CVE ID, the disputed information, and supporting evidence. A dispute does not itself reject a record.

Find the responsible CNA →Official dispute and escalation process ↗

CVE CVE-2026-93834

Enrichment coverage

NVDAvailable

Checked 31/10/2026, 11:30:32 UTC

GHSAAvailable

Checked 31/10/2026, 11:30:32 UTC

EUVDAvailable

Checked 31/10/2026, 11:30:32 UTC

EPSSAvailable

Checked 31/10/2026, 11:30:32 UTC

Additional source evidence

ENISA EUVD · EUVD-2026-87092

CVSS 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Checked 31/10/2026, 11:30:32 UTC

GitHub Advisory Database · GHSA-86c2-8qp8-q2vh

CVSS 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Checked 31/10/2026, 11:30:32 UTC

FIRST EPSS · CVE-2026-93834

EPSS 0.40% probability of exploitation in the next 30 days. Percentile: 34.72% · 2026-10-30

Checked 31/10/2026, 11:30:32 UTC

NVD · CVE-2026-93834

CVSS 8.8 CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H

Checked 31/10/2026, 11:30:32 UTC

Sponsored by MoxsoBuild security habits with adaptive training and phishing simulations.View as JSON

Qemu-kvm: 9pfs: use-after-free race in tlcreate/twalk allows vm guest escape

Severity and exploitation

What this means

Attack conditions

Affected versions

Red Hat Enterprise Linux 10

affected

unaffected

unknown

Red Hat Enterprise Linux 6

affected

unaffected

unknown

Red Hat Enterprise Linux 7

affected

unaffected

unknown

Red Hat Enterprise Linux 7

affected

unaffected

unknown

Red Hat Enterprise Linux 8

affected

unaffected

unknown

Red Hat Enterprise Linux 8

affected

unaffected

unknown

Red Hat Enterprise Linux 9

affected

unaffected

unknown

Red Hat Enterprise Linux for NVIDIA 26

affected

unaffected

unknown

Red Hat OpenShift Container Platform 4

affected

unaffected

unknown

Red Hat OpenShift Container Platform 4

affected

unaffected

unknown

Red Hat OpenShift Container Platform 5

affected

unaffected

unknown

Red Hat OpenStack Platform 13 (Queens)

affected

unaffected

unknown

What to do

Public exploit evidence

Original source description

References

Inside the record

Evidence available

Original records

Underlying weaknesses

Timeline

Advisory published

Source updated

Last imported by cve.new

What changed