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CVE-2022-50755

Status: DeferredHigh (7.8)—

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

udf: Avoid double brelse() in udf_rename()

syzbot reported a warning like below [1]:

The cause of the issue is that brelse() is called on both ofibh.sbh and ofibh.ebh by udf_find_entry() when it returns NULL. However, brelse() is called by udf_rename(), too. So, b_count on buffer_head becomes unbalanced.

This patch fixes the issue by not calling brelse() by udf_rename() when udf_find_entry() returns NULL.

Technical details traces, logs and code from the original report
VFS: brelse: Trying to free free buffer
WARNING: CPU: 2 PID: 7301 at fs/buffer.c:1145 __brelse+0x67/0xa0
...
Call Trace:
 <TASK>
 invalidate_bh_lru+0x99/0x150
 smp_call_function_many_cond+0xe2a/0x10c0
 ? generic_remap_file_range_prep+0x50/0x50
 ? __brelse+0xa0/0xa0
 ? __mutex_lock+0x21c/0x12d0
 ? smp_call_on_cpu+0x250/0x250
 ? rcu_read_lock_sched_held+0xb/0x60
 ? lock_release+0x587/0x810
 ? __brelse+0xa0/0xa0
 ? generic_remap_file_range_prep+0x50/0x50
 on_each_cpu_cond_mask+0x3c/0x80
 blkdev_flush_mapping+0x13a/0x2f0
 blkdev_put_whole+0xd3/0xf0
 blkdev_put+0x222/0x760
 deactivate_locked_super+0x96/0x160
 deactivate_super+0xda/0x100
 cleanup_mnt+0x222/0x3d0
 task_work_run+0x149/0x240
 ? task_work_cancel+0x30/0x30
 do_exit+0xb29/0x2a40
 ? reacquire_held_locks+0x4a0/0x4a0
 ? do_raw_spin_lock+0x12a/0x2b0
 ? mm_update_next_owner+0x7c0/0x7c0
 ? rwlock_bug.part.0+0x90/0x90
 ? zap_other_threads+0x234/0x2d0
 do_group_exit+0xd0/0x2a0
 __x64_sys_exit_group+0x3a/0x50
 do_syscall_64+0x34/0xb0
 entry_SYSCALL_64_after_hwframe+0x63/0xcd

CVSS

Exploitation probability (EPSS)

EPSS (Exploit Prediction Scoring System, FIRST) estimates how likely a vulnerability is to be exploited in the wild within 30 days. It complements CVSS (impact) and CISA KEV (confirmed exploitation).

🎯 ATT&CK techniques

How this vulnerability is exploited and what the attacker gains, in MITRE ATT&CK terms.

Acceso local (AV:L) sin interacción del usuario en kernel Linux. Causa doble liberación de memoria (double brelse) que puede llevar a denegación de servicio o corrupción de memoria.

Inferred by our analysis agent from the official description, CVSS vector and CWE, and checked by a supervisor. May contain errors.

🛡️ ATT&CK mitigations that cover these techniques

Threat Intelligence ProgramFilter Network TrafficExecution PreventionApplication Isolation and SandboxingExploit ProtectionUpdate Software

Affected technologies (1)

⚠ AI-inferred from the description — NVD hasn't analyzed this CVE yet, these aren't verified CPEs.

Linux — Linux KernelAI

References

Raw JSON (NVD)

Show
{
  "id": "CVE-2022-50755",
  "cveTags": [],
  "metrics": {
    "cvssMetricV31": [
      {
        "type": "Secondary",
        "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "cvssData": {
          "scope": "UNCHANGED",
          "version": "3.1",
          "baseScore": 7.8,
          "attackVector": "LOCAL",
          "baseSeverity": "HIGH",
          "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
          "integrityImpact": "HIGH",
          "userInteraction": "NONE",
          "attackComplexity": "LOW",
          "availabilityImpact": "HIGH",
          "privilegesRequired": "LOW",
          "confidentialityImpact": "HIGH"
        },
        "impactScore": 5.9,
        "exploitabilityScore": 1.8
      }
    ]
  },
  "affected": [
    {
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
      "affectedData": [
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "78eba2778ae10fb2a9d450e14d26eb6f6bf1f906",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "9d2cad69547abea961fa80426d600b861de1952b",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "d6da7ec0f94f5208c848e0e94b70f54a0bd9c587",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "156d440dea97deada629bb51cb17887abd862605",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "40dba68d418237b1ae2beaa06d46a94dd946278e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "e7a6a53c871460727be09f4414ccb29fb8697526",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "4fca09045509f5bde8fc28e68fbca38cb4bdcf2e",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "090bf49833c51da297ec74f98ad2bf44daea9311",
              "versionType": "git"
            },
            {
              "status": "affected",
              "version": "231473f6ddcef9c01993e0bfe36acc6f8e425c31",
              "lessThan": "c791730f2554a9ebb8f18df9368dc27d4ebc38c2",
              "versionType": "git"
            }
          ],
          "programFiles": [
            "fs/udf/namei.c"
          ],
          "defaultStatus": "unaffected"
        },
        {
          "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
          "vendor": "Linux",
          "product": "Linux",
          "versions": [
            {
              "status": "affected",
              "version": "4.2"
            },
            {
              "status": "unaffected",
              "version": "0",
              "lessThan": "4.2",
              "versionType": "semver"
            },
            {
              "status": "unaffected",
              "version": "4.9.337",
              "versionType": "semver",
              "lessThanOrEqual": "4.9.*"
            },
            {
              "status": "unaffected",
              "version": "4.14.303",
              "versionType": "semver",
              "lessThanOrEqual": "4.14.*"
            },
            {
              "status": "unaffected",
              "version": "4.19.270",
              "versionType": "semver",
              "lessThanOrEqual": "4.19.*"
            },
            {
              "status": "unaffected",
              "version": "5.4.229",
              "versionType": "semver",
              "lessThanOrEqual": "5.4.*"
            },
            {
              "status": "unaffected",
              "version": "5.10.163",
              "versionType": "semver",
              "lessThanOrEqual": "5.10.*"
            },
            {
              "status": "unaffected",
              "version": "5.15.86",
              "versionType": "semver",
              "lessThanOrEqual": "5.15.*"
            },
            {
              "status": "unaffected",
              "version": "6.0.16",
              "versionType": "semver",
              "lessThanOrEqual": "6.0.*"
            },
            {
              "status": "unaffected",
              "version": "6.1.2",
              "versionType": "semver",
              "lessThanOrEqual": "6.1.*"
            },
            {
              "status": "unaffected",
              "version": "6.2",
              "versionType": "original_commit_for_fix",
              "lessThanOrEqual": "*"
            }
          ],
          "programFiles": [
            "fs/udf/namei.c"
          ],
          "defaultStatus": "affected"
        }
      ]
    }
  ],
  "published": "2025-12-24T13:16:02.250",
  "references": [
    {
      "url": "https://git.kernel.org/stable/c/090bf49833c51da297ec74f98ad2bf44daea9311",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/156d440dea97deada629bb51cb17887abd862605",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/40dba68d418237b1ae2beaa06d46a94dd946278e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/4fca09045509f5bde8fc28e68fbca38cb4bdcf2e",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/78eba2778ae10fb2a9d450e14d26eb6f6bf1f906",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/9d2cad69547abea961fa80426d600b861de1952b",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/c791730f2554a9ebb8f18df9368dc27d4ebc38c2",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/d6da7ec0f94f5208c848e0e94b70f54a0bd9c587",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    },
    {
      "url": "https://git.kernel.org/stable/c/e7a6a53c871460727be09f4414ccb29fb8697526",
      "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
    }
  ],
  "vulnStatus": "Deferred",
  "descriptions": [
    {
      "lang": "en",
      "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nudf: Avoid double brelse() in udf_rename()\n\nsyzbot reported a warning like below [1]:\n\nVFS: brelse: Trying to free free buffer\nWARNING: CPU: 2 PID: 7301 at fs/buffer.c:1145 __brelse+0x67/0xa0\n...\nCall Trace:\n <TASK>\n invalidate_bh_lru+0x99/0x150\n smp_call_function_many_cond+0xe2a/0x10c0\n ? generic_remap_file_range_prep+0x50/0x50\n ? __brelse+0xa0/0xa0\n ? __mutex_lock+0x21c/0x12d0\n ? smp_call_on_cpu+0x250/0x250\n ? rcu_read_lock_sched_held+0xb/0x60\n ? lock_release+0x587/0x810\n ? __brelse+0xa0/0xa0\n ? generic_remap_file_range_prep+0x50/0x50\n on_each_cpu_cond_mask+0x3c/0x80\n blkdev_flush_mapping+0x13a/0x2f0\n blkdev_put_whole+0xd3/0xf0\n blkdev_put+0x222/0x760\n deactivate_locked_super+0x96/0x160\n deactivate_super+0xda/0x100\n cleanup_mnt+0x222/0x3d0\n task_work_run+0x149/0x240\n ? task_work_cancel+0x30/0x30\n do_exit+0xb29/0x2a40\n ? reacquire_held_locks+0x4a0/0x4a0\n ? do_raw_spin_lock+0x12a/0x2b0\n ? mm_update_next_owner+0x7c0/0x7c0\n ? rwlock_bug.part.0+0x90/0x90\n ? zap_other_threads+0x234/0x2d0\n do_group_exit+0xd0/0x2a0\n __x64_sys_exit_group+0x3a/0x50\n do_syscall_64+0x34/0xb0\n entry_SYSCALL_64_after_hwframe+0x63/0xcd\n\nThe cause of the issue is that brelse() is called on both ofibh.sbh\nand ofibh.ebh by udf_find_entry() when it returns NULL.  However,\nbrelse() is called by udf_rename(), too.  So, b_count on buffer_head\nbecomes unbalanced.\n\nThis patch fixes the issue by not calling brelse() by udf_rename()\nwhen udf_find_entry() returns NULL."
    }
  ],
  "lastModified": "2026-08-04T10:18:23.497",
  "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}