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Linux KernelOperating system · Linux

CVE-2026-53039

MEDIUM · 5.5 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 5.10.258 / 5.15.209 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
In the Linux kernel, the following vulnerability has been resolved: ocfs2: validate group add input before caching [BUG] OCFS2_IOC_GROUP_ADD can trigger a BUG_ON in ocfs2_set_new_buffer_uptodate(): kernel BUG at fs/ocfs2/uptodate.c:509! Oops: invalid opcode: 0000 [#1] SMP KASAN NOPTI RIP: 0010:ocfs2_set_new_buffer_uptodate+0x194/0x1e0 fs/ocfs2/uptodate.c:509 Code: ffffe88f 42b9fe4c 89e64889 dfe8b4df Call Trace: ocfs2_group_add+0x3f1/0x1510 fs/ocfs2/resize.c:507 ocfs2_ioctl+0x309/0x6e0 fs/ocfs2/ioctl.c:887 vfs_ioctl fs/ioctl.c:51 [inline] __do_sys_ioctl fs/ioctl.c:597 [inline] __se_sys_ioctl fs/ioctl.c:583 [inline] __x64_sys_ioctl+0x197/0x1e0 fs/ioctl.c:583 x64_sys_call+0x1144/0x26a0 arch/x86/include/generated/asm/syscalls_64.h:17 do_syscall_x64 arch/x86/entry/syscall_64.c:63 [inline] do_syscall_64+0x93/0xf80 arch/x86/entry/syscall_64.c:94 entry_SYSCALL_64_after_hwframe+0x76/0x7e RIP: 0033:0x7bbfb55a966d [CAUSE] ocfs2_group_add() calls ocfs2_set_new_buffer_uptodate() on a user-controlled group block before ocfs2_verify_group_and_input() validates that block number. That helper is only valid for newly allocated metadata and asserts that the block is not already present in the chosen metadata cache. The code also uses INODE_CACHE(inode) even though the group descriptor belongs to main_bm_inode and later journal accesses use that cache context instead. [FIX] Validate the on-disk group descriptor before caching it, then add it to the metadata cache tracked by INODE_CACHE(main_bm_inode). Keep the validation failure path separate from the later cleanup path so we only remove the buffer from that cache after it has actually been inserted. This keeps the group buffer lifetime consistent across validation, journaling, and cleanup.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

In the ocfs2 filesystem, the OCFS2_IOC_GROUP_ADD ioctl handler calls ocfs2_set_new_buffer_uptodate() to cache a group descriptor buffer BEFORE validating the input with ocfs2_verify_group_and_input(). Additionally, it incorrectly uses INODE_CACHE(inode) instead of INODE_CACHE(main_bm_inode). This allows a user to trigger a BUG_ON assertion in the metadata cache, causing a kernel panic (denial of service).

MitigationApply the kernel patch to reorder validation before caching and use the correct metadata cache (main_bm_inode). Until patched, restrict access to ocfs2 filesystems or the OCFS2_IOC_GROUP_ADD ioctl to prevent local denial of service.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.25, < 5.10.258>= 5.11, < 5.15.209>= 5.16, < 6.1.175>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if ocfs2 filesystem is in use
    Run 'lsmod | grep ocfs2' to check if the ocfs2 kernel module is loaded, or check /proc/filesystems for ocfs2, or check 'mount' output for any ocfs2 mounts
    Affected if ocfs2 module is loaded OR an ocfs2 filesystem is mounted on the system
  2. Identify the running kernel version
    Run 'uname -r' to get the kernel version, then compare it against the affected ranges: < 5.10.258, >= 5.11 to < 5.15.209, >= 5.16 to < 6.1.175, >= 6.2 to < 6.6.141, >= 6.7 to < 6.12.91, >= 6.13 to < 6.18.33, >= 6.19 to < 7.0.10
    Affected if The kernel version falls within any of the listed affected version ranges
  3. Verify ocfs2 filesystem is mounted with write access
    Run 'mount | grep ocfs2' and check for any ocfs2 mounts; the vulnerability requires the OCFS2_IOC_GROUP_ADD ioctl which needs write access to an ocfs2-mounted filesystem
    Affected if An ocfs2 filesystem is mounted with read-write access (the 'rw' mount option)
  4. Confirm write access to ocfs2 mount point exists
    Check if a local user or process can access an ocfs2-mounted filesystem with write permissions; the ioctl requires write access to the filesystem
    Affected if Non-privileged users or processes have write access to an ocfs2 mount point

The system is affected if it runs a vulnerable kernel version within the affected ranges AND has an ocfs2 filesystem mounted with write access that can be used to trigger the OCFS2_IOC_GROUP_ADD ioctl.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.10.258 / 5.15.209 / 6.1.175 or later
Fixed in 5.10.2585.15.2096.1.175
Interim mitigation

Apply the kernel patch to reorder validation before caching and use the correct metadata cache (main_bm_inode). Until patched, restrict access to ocfs2 filesystems or the OCFS2_IOC_GROUP_ADD ioctl to prevent local denial of service.

Recommended fix High confidence

Upgrade to kernel version 5.10.258 or later (if using 5.10.x), 5.15.209 or later (if using 5.15.x), 6.1.175 or later (if using 6.1.x), or 6.6.141 or later (if using 6.2-6.6.x). For newer branches (6.7+), any version after these milestone releases includes the fix.

  1. Identify the current kernel version using `uname -r` or `cat /proc/version`
  2. Verify that the system uses the OCFS2 filesystem by checking mount points with `mount | grep ocfs2` or `cat /proc/mounts`
  3. Schedule a maintenance window for kernel upgrade (this requires system downtime)
  4. Backup critical data as a precautionary measure
  5. Upgrade the Linux kernel to one of the fixed versions: 5.10.258+, 5.15.209+, 6.1.175+, or 6.6.141+ (or a later stable release)
  6. For package-based systems: use your distribution's package manager (e.g., `apt-get update && apt-get upgrade`, `yum update`, or `dnf upgrade`) to install the new kernel package
  7. For custom-built kernels: obtain the OCFS2 fix from the kernel source commit and rebuild the kernel
  8. Reboot the system into the new kernel using `shutdown -r now` or `reboot`
Caveat Kernel upgrades may require rebooting services and could have compatibility implications with custom modules or drivers. Ensure custom OCFS2 modules match the new kernel version.

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation2.0 h
  • Implementation4.0 h
  • Testing6.0 h
  • Review / QA2.0 h
14.0 hours of engineering $2,380
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

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Peer-ranked notes from engineers who’ve handled CVE-2026-53039 in production — separate from our analysis above.

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