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GHSA-PWHW-9CFC-QQQX

Vulnerability from github – Published: 2026-09-04 18:31 – Updated: 2026-09-04 18:31

Details

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

futex/pi: Reject cross-mm private futex owners

A private futex key borrows the waiter's mm without taking an mm_users reference. Nevertheless, attach_to_pi_owner() currently accepts an owner from a different address space and copies the private key into the owner's PI state.

When that owner exits, exit_pi_state_list() uses the saved key to find the hash bucket and acquires a reference to the waiter's private hash. If the last user of the waiter's mm exits concurrently, futex_hash_free() frees the hash while the owner still uses its bucket and reference.

Prevent this by validating in attach_to_pi_owner() that, for private futexes, the owner mm and waiter mm are the same. Perform the check with the owner's pi_lock held and after validating owner::futex::state to serialize against a concurrent PI-state exit cleanup.

[ tglx: Amended comment ]

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{
  "affected": [],
  "aliases": [
    "CVE-2026-80778"
  ],
  "database_specific": {
    "cwe_ids": [],
    "github_reviewed": false,
    "github_reviewed_at": null,
    "nvd_published_at": "2026-09-04T16:18:03Z",
    "severity": null
  },
  "details": "In the Linux kernel, the following vulnerability has been resolved:\n\nfutex/pi: Reject cross-mm private futex owners\n\nA private futex key borrows the waiter\u0027s mm without taking an mm_users\nreference. Nevertheless, attach_to_pi_owner() currently accepts an owner\nfrom a different address space and copies the private key into the owner\u0027s\nPI state.\n\nWhen that owner exits, exit_pi_state_list() uses the saved key to find the\nhash bucket and acquires a reference to the waiter\u0027s private hash. If the\nlast user of the waiter\u0027s mm exits concurrently, futex_hash_free() frees\nthe hash while the owner still uses its bucket and reference.\n\nPrevent this by validating in attach_to_pi_owner() that, for private\nfutexes, the owner mm and waiter mm are the same. Perform the check with\nthe owner\u0027s pi_lock held and after validating owner::futex::state to\nserialize against a concurrent PI-state exit cleanup.\n\n[ tglx: Amended comment ]",
  "id": "GHSA-pwhw-9cfc-qqqx",
  "modified": "2026-09-04T18:31:25Z",
  "published": "2026-09-04T18:31:25Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-80778"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/2b92e5562653b5293529f63b0300837d9dcedbd7"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/43b148d796aa338858792d0167cebdc12b8cb4b9"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/59b3732f95dda1fbd2234514d35f4fb6b5bb6d85"
    },
    {
      "type": "WEB",
      "url": "https://git.kernel.org/stable/c/f7fb3e07752688842cbe0b85cf0d98c2fbf76b68"
    }
  ],
  "schema_version": "1.4.0",
  "severity": []
}

CVE-2026-80778 (GCVE-0-2026-80778)

Vulnerability from cvelistv5 – Published: 2026-09-04 15:12 – Updated: 2026-09-04 15:12

Title

futex/pi: Reject cross-mm private futex owners

Summary

In the Linux kernel, the following vulnerability has been resolved: futex/pi: Reject cross-mm private futex owners A private futex key borrows the waiter's mm without taking an mm_users reference. Nevertheless, attach_to_pi_owner() currently accepts an owner from a different address space and copies the private key into the owner's PI state. When that owner exits, exit_pi_state_list() uses the saved key to find the hash bucket and acquires a reference to the waiter's private hash. If the last user of the waiter's mm exits concurrently, futex_hash_free() frees the hash while the owner still uses its bucket and reference. Prevent this by validating in attach_to_pi_owner() that, for private futexes, the owner mm and waiter mm are the same. Perform the check with the owner's pi_lock held and after validating owner::futex::state to serialize against a concurrent PI-state exit cleanup. [ tglx: Amended comment ]

Severity

No CVSS data available.

Assigner

Linux mitre root

References

4 references

URL	Tags
https://git.kernel.org/stable/c/2b92e5562653b5293…
https://git.kernel.org/stable/c/f7fb3e07752688842…
https://git.kernel.org/stable/c/43b148d796aa33885…
https://git.kernel.org/stable/c/59b3732f95dda1fbd…

Impacted products

2 products

Vendor	Product	Version
Linux	Linux	Affected: 80367ad01d93ac781b0e1df246edaf006928002f , < 2b92e5562653b5293529f63b0300837d9dcedbd7 (git) Affected: 80367ad01d93ac781b0e1df246edaf006928002f , < f7fb3e07752688842cbe0b85cf0d98c2fbf76b68 (git) Affected: 80367ad01d93ac781b0e1df246edaf006928002f , < 43b148d796aa338858792d0167cebdc12b8cb4b9 (git) Affected: 80367ad01d93ac781b0e1df246edaf006928002f , < 59b3732f95dda1fbd2234514d35f4fb6b5bb6d85 (git)
Linux	Linux	Affected: 6.16 Unaffected: 0 , < 6.16 (semver) Unaffected: 6.18.47 , ≤ 6.18.* (semver) Unaffected: 7.1.11 , ≤ 7.1.* (semver) Unaffected: 7.2.1 , ≤ 7.2.* (semver) Unaffected: 7.3-rc1 , ≤ * (original_commit_for_fix)

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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.

Detection rules are retrieved from Rulezet.

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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