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GHSA-86C2-8QP8-Q2VH

Vulnerability from github – Published: 2026-09-25 15:31 – Updated: 2026-09-25 15:31

Details

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.

Severity

8.8 (High)


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

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{
  "affected": [],
  "aliases": [
    "CVE-2026-93834"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-416"
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    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-25T14:17:24Z",
    "severity": "HIGH"
  },
  "details": "A use-after-free vulnerability was found in QEMU\u0027s 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.",
  "id": "GHSA-86c2-8qp8-q2vh",
  "modified": "2026-09-25T15:31:48Z",
  "published": "2026-09-25T15:31:48Z",
  "references": [
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      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-93834"
    },
    {
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    },
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      "type": "WEB",
      "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2537939"
    },
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      "url": "https://gitlab.com/qemu-project/qemu/-/work_items/4491"
    }
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  "schema_version": "1.4.0",
  "severity": [
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      "score": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ]
}

CVE-2026-93834 (GCVE-0-2026-93834)

Vulnerability from cvelistv5 – Published: 2026-09-25 13:36 – Updated: 2026-09-25 13:50

Title

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

Summary

Severity

8.8 (High)


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

SSVC

Exploitation: poc Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-09-25 13:49 UTC

CWE

CWE-416 - Use After Free

Assigner

redhat redhat root

References

3 references

URL	Tags
https://access.redhat.com/security/cve/CVE-2026-93834	vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2537939	issue-trackingx_refsource_REDHAT
https://gitlab.com/qemu-project/qemu/-/work_items/4491

Impacted products

8 products

Vendor	Product	Version
Red Hat	Red Hat Enterprise Linux 10	cpe:/o:redhat:enterprise_linux:10
Red Hat	Red Hat Enterprise Linux 6	cpe:/o:redhat:enterprise_linux:6
Red Hat	Red Hat Enterprise Linux 7	cpe:/o:redhat:enterprise_linux:7
Red Hat	Red Hat Enterprise Linux 8	cpe:/o:redhat:enterprise_linux:8
Red Hat	Red Hat Enterprise Linux 9	cpe:/o:redhat:enterprise_linux:9
Red Hat	Red Hat Enterprise Linux for NVIDIA 26	cpe:/a:redhat:enterprise_linux_nvidia:
Red Hat	Red Hat OpenShift Container Platform 4	cpe:/a:redhat:openshift:4
Red Hat	Red Hat OpenStack Platform 13 (Queens)	cpe:/a:redhat:openstack:13

Date Public

2026-09-22 00:00

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Sightings

Author	Source	Type	Date	Other

Nomenclature

Seen: The vulnerability was mentioned, discussed, or observed by the user.
Confirmed: The vulnerability has been validated from an analyst's perspective.
Published Proof of Concept: A public proof of concept is available for this vulnerability.
Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
Not confirmed: The user expressed doubt about the validity of the vulnerability.
Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.

The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base model, served locally by ML-Gateway. They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
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GHSA-86C2-8QP8-Q2VH

CVE-2026-93834 (GCVE-0-2026-93834)

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