Vulnerability-Lookup

GHSA-78GX-8V3C-JQWC

Vulnerability from github – Published: 2026-07-09 18:31 – Updated: 2026-07-09 18:31

Details

varstored is a component of the Xapi toolstack handling UEFI Variables for a VM. It has a communication path with OVMF inside the VM involving mapping a buffer prepared by OVMF.

Within varstored, there were insufficient compiler barriers, creating TOCTOU issues with data in the shared buffer.

The exact vulnerable behaviour depends on the code generated by the compiler. In a build of varstored using default settings, the attacker can control an index used in a jump table.

Severity

9.4 (Critical)


                  
                    CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

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{
  "affected": [],
  "aliases": [
    "CVE-2025-58151"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-367"
    ],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-07-09T16:16:33Z",
    "severity": "CRITICAL"
  },
  "details": "varstored is a component of the Xapi toolstack handling UEFI Variables\nfor a VM.  It has a communication path with OVMF inside the VM involving\nmapping a buffer prepared by OVMF.\n\nWithin varstored, there were insufficient compiler barriers, creating\nTOCTOU issues with data in the shared buffer.\n\nThe exact vulnerable behaviour depends on the code generated by the\ncompiler.  In a build of varstored using default settings, the attacker\ncan control an index used in a jump table.",
  "id": "GHSA-78gx-8v3c-jqwc",
  "modified": "2026-07-09T18:31:50Z",
  "published": "2026-07-09T18:31:50Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2025-58151"
    },
    {
      "type": "WEB",
      "url": "https://xenbits.xen.org/xsa/advisory-478.html"
    },
    {
      "type": "WEB",
      "url": "http://www.openwall.com/lists/oss-security/2026/01/27/2"
    },
    {
      "type": "WEB",
      "url": "http://xenbits.xen.org/xsa/advisory-478.html"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X",
      "type": "CVSS_V4"
    }
  ]
}

CVE-2025-58151 (GCVE-0-2025-58151)

Vulnerability from cvelistv5 – Published: 2026-07-09 14:45 – Updated: 2026-07-09 15:41

Title

varstored: TOCTOU issues with mapped guest memory

Summary

varstored is a component of the Xapi toolstack handling UEFI Variables for a VM. It has a communication path with OVMF inside the VM involving mapping a buffer prepared by OVMF. Within varstored, there were insufficient compiler barriers, creating TOCTOU issues with data in the shared buffer. The exact vulnerable behaviour depends on the code generated by the compiler. In a build of varstored using default settings, the attacker can control an index used in a jump table.

Severity

9.4 (Critical)


                        
                          CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H

SSVC

Exploitation: none Automatable: no Technical Impact: total

CISA Coordinator · CISA-ADP (v2.0.3)

Decision recorded 2026-07-09 15:40 UTC

CWE

CWE-367 - Time-of-check time-of-use (TOCTOU) race condition

Assigner

XEN mitre root Scorecard

References

3 references

URL	Tags
https://xenbits.xen.org/xsa/advisory-478.html
http://www.openwall.com/lists/oss-security/2026/01/27/2
http://xenbits.xen.org/xsa/advisory-478.html

Impacted products

1 product

Vendor	Product	Version
Xen	varstored	Affected: all

Date Public

2026-01-27 13:00

Credits

This issue was discovered by Teddy Astie of Vates.

Show details on NVD website

JSON

To clipboard

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        "providerMetadata": {
          "dateUpdated": "2026-07-09T15:05:08.753Z",
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          },
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            "url": "http://xenbits.xen.org/xsa/advisory-478.html"
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        "title": "CVE Program Container"
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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.
Browse all ATT&CK techniques and the vulnerabilities related to each.

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GHSA-78GX-8V3C-JQWC

CVE-2025-58151 (GCVE-0-2025-58151)

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