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CVE-2026-53341 (GCVE-0-2026-53341)

Vulnerability from cvelistv5 – Published: 2026-07-01 13:32 – Updated: 2026-08-05 12:35
VLAI
Title
fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh()
Summary
In the Linux kernel, the following vulnerability has been resolved: fhandle: fix UAF due to unlocked ->mnt_ns read in may_decode_fh() may_decode_fh() accesses mount::mnt_ns without holding any locks; that means the mount can concurrently be unmounted, and the mnt_namespace can concurrently be freed after an RCU grace period. This race can happens as follows, assuming that the mount point was created by open_tree(..., OPEN_TREE_CLONE): thread 1 thread 2 RCU __do_sys_open_by_handle_at do_handle_open handle_to_path may_decode_fh is_mounted [mount::mnt_ns access] [mount::mnt_ns access] __do_sys_close fput_close_sync __fput dissolve_on_fput umount_tree class_namespace_excl_destructor namespace_unlock free_mnt_ns mnt_ns_tree_remove call_rcu(mnt_ns_release_rcu) mnt_ns_release_rcu mnt_ns_release kfree [mnt_namespace::user_ns access] **UAF** Fix it by taking rcu_read_lock() around the mount::mnt_ns access, like in __prepend_path(). Additionally, document the semantics of mount::mnt_ns, and use WRITE_ONCE() for writers that can race with lockless readers. This bug is unreachable unless one of the following is set: - CONFIG_PREEMPTION - CONFIG_RCU_STRICT_GRACE_PERIOD because it requires an RCU grace period to happen during a syscall without an explicit preemption. This doesn't seem to have interesting security impact; worst-case, it could leak the result of an integer comparison to userspace (from the level check in cap_capable()), cause an endless loop, or crash the kernel by dereferencing an invalid address.
Severity
7.8 (High)
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 620c266f394932e5decc4b34683a75dfc59dc2f4 , < 15ea8dc42a02259d49dee38a658d40f60fcd75ed (git)
Affected: 620c266f394932e5decc4b34683a75dfc59dc2f4 , < 32138633e51e6db59e474765cf93268c92b42888 (git)
Affected: 620c266f394932e5decc4b34683a75dfc59dc2f4 , < a8ed2c29fcfdac78db96c9da4e659c8a513f2a94 (git)
Affected: 620c266f394932e5decc4b34683a75dfc59dc2f4 , < 40ab6644b99685755f740b872c00ef40d9aa870e (git)
guessed Create a notification for this product.
Linux Linux Affected: 6.11
Unaffected: 0 , < 6.11 (semver)
Unaffected: 6.12.95 , ≤ 6.12.* (semver)
Unaffected: 6.18.36 , ≤ 6.18.* (semver)
Unaffected: 7.0.13 , ≤ 7.0.* (semver)
Unaffected: 7.1 , ≤ * (original_commit_for_fix)
guessed Create a notification for this product.
Show details on NVD website
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          }
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        "vulnStatus": "Analyzed",
        "weaknesses": [
          {
            "description": [
              {
                "lang": "en",
                "value": "CWE-416"
              }
            ],
            "source": "nvd@nist.gov",
            "type": "Primary"
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    "redhat_vex": {
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      "current_release_date": "2026-07-18T08:05:25+00:00",
      "cve": "CVE-2026-53341",
      "id": "CVE-2026-53341",
      "initial_release_date": "2026-07-01T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: fhandle: fix UAF due to unlocked -\u003emnt_ns read in may_decode_fh()",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-53341.json",
      "version": "3"
    },
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      "cve": "CVE-2026-53341",
      "id": "CVE-2026-53341",
      "initial_release_date": "2026-07-03T03:04:09Z",
      "product_status:known_affected": "17",
      "product_status:known_not_affected": "342",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-53341",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-53341.json",
      "version": "5"
    }
  }
}



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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.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.