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CVE-2023-53626 (GCVE-0-2023-53626)

Vulnerability from cvelistv5 – Published: 2025-10-07 15:19 – Updated: 2026-08-05 09:15
VLAI
Title
ext4: fix possible double unlock when moving a directory
Summary
In the Linux kernel, the following vulnerability has been resolved: ext4: fix possible double unlock when moving a directory
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: 8dac5a63cf79707b547ea3d425fead5f4482198f , < c16cbd8233d6c58fc488545393e49b5d55729990 (git)
Affected: 0c440f14558bfacd22c6935ae1fd4b2a09e96b5d , < 020166bc6669ca9fb267ebd96bd88c4fb64a5d46 (git)
Affected: c50fc503ee1b97f12c98e26afc39fdaebebcf04f , < 1c93c42c7bb23057bde8a0a2ab834927ff64d20c (git)
Affected: b0bb13612292ca90fa4c2a7e425375649bc50d3e , < e71eb4dca41f0f36823724ced0406bb2dbdd5506 (git)
Affected: 291cd19d107e197306869cb3237c1bba62d13182 , < 43ce288ab5d7274a4a141d7f5e3ed2ab7b41f8a2 (git)
Affected: 0813299c586b175d7edb25f56412c54b812d0379 , < 70e42feab2e20618ddd0cbfc4ab4b08628236ecd (git)
guessed Create a notification for this product.
Linux Linux Affected: 5.4.237 , < 5.4.238 (semver)
Affected: 5.10.175 , < 5.10.176 (semver)
Affected: 5.15.103 , < 5.15.104 (semver)
Affected: 6.1.20 , < 6.1.21 (semver)
Affected: 6.2.7 , < 6.2.8 (semver)
guessed Create a notification for this product.
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              "value": "AV:L - The bug is reached through the `rename(2)` syscall on a locally mounted ext4 filesystem; no network or remote peer is involved. The attacker needs local access to mount/attach the crafted ext4 image and issue the rename.\nAC:L - The `ext4_rename_dir_prepare()` failure is deterministic with a crafted `.`/`..` entry, so the double `up_write()` always occurs, and the attacker controls every thread contending for the moved directory\u0027s `i_rwsem`. The unlock window spans a sleeping `ext4_journal_stop()`, so winning the mutual-exclusion-break race is easy and infinitely retryable.\nPR:L - An ordinary unprivileged local user suffices: on mainstream desktop/kiosk deployments udisks2\u0027s default polkit `allow_active` loop-setup and removable-media automount let a console user mount an arbitrary attacker-authored ext4 image, and the `rename(2)` itself needs only write access to the attacker\u0027s own directories.\nUI:N - In the automount/loop-setup scenario the attacker performs the mount and the rename themselves; no second user has to be induced into any action.\nS:U - The corrupted `i_rwsem`, the resulting concurrent directory mutation, and any memory corruption all stay within the kernel\u0027s own security authority. No VM, IOMMU, or sandbox boundary is crossed.\nC:H - Breaking exclusion on a directory inode lets concurrent readers/writers race the inline-dir-to-extent conversion, so dirent parsing runs against the raw inode\u0027s `i_block`/xattr region under a stale format assumption, exposing adjacent kernel memory through `readdir`/`getdents`, and the buffer_head UAF this enables gives a further read primitive.\nI:H - The silent release of another task\u0027s exclusive `i_rwsem` allows two threads to run ext4 dirent add/delete, htree split, and inline-to-extent conversion on the same inode simultaneously, producing metadata and heap corruption \u2014 the exact corruption class `0813299c586b` was written to prevent \u2014 which is leverageable for controlled writes.\nA:H - When the lock is free at the second unlock, the rwsem count underflows to `~0UL` with no owner, so every later `down_read`/`down_write` on that directory blocks permanently in uninterruptible sleep, hanging the directory, the unmount, and eventually tripping the hung-task watchdog. The corruption path independently yields oopses and `errors=remount-ro`/`panic` filesystem shutdown."
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    "dateReserved": "2025-10-07T15:16:59.656Z",
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    "redhat_vex": {
      "aggregate_severity": "Moderate",
      "current_release_date": "2026-08-04T19:16:56+00:00",
      "cve": "CVE-2023-53626",
      "id": "CVE-2023-53626",
      "initial_release_date": "2023-01-01T00:00:00+00:00",
      "product_status:known_affected": "198",
      "product_status:known_not_affected": "76",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: ext4: fix possible double unlock when moving a directory",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2023/cve-2023-53626.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "moderate",
      "current_release_date": "2026-08-29T02:06:05Z",
      "cve": "CVE-2023-53626",
      "id": "CVE-2023-53626",
      "initial_release_date": "2025-10-08T23:31:13Z",
      "product_status:known_affected": "354",
      "product_status:known_not_affected": "395",
      "product_status:recommended": "225",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2023-53626",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2023-53626.json",
      "version": "23"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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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.