CVE-2023-53618

Medium

In the Linux kernel, the following vulnerability has been resolved: btrfs: reject invalid reloc tree root keys with stack dump [BUG] Syzbot reported a crash that an ASSERT() got triggered inside prepare_to_merge(). That ASSERT() makes sure the reloc tree is properly pointed back by its subvolume tree. [CAUSE] After more debugging output, it turns out we had an invalid reloc tree: BTRFS error (device loop1): reloc tree mismatch, root 8 has no reloc root, expect reloc root key (-8, 132, 8) gen 17 Note the above root key is (TREE_RELOC_OBJECTID, ROOT_ITEM, QUOTA_TREE_OBJECTID), meaning it's a reloc tree for quota tree. But reloc trees can only exist for subvolumes, as for non-subvolume trees, we just COW the involved tree block, no need to create a reloc tree since those tree blocks won't be shared with other trees. Only subvolumes tree can share tree blocks with other trees (thus they have BTRFS_ROOT_SHAREABLE flag). Thus this new debug output proves my previous assumption that corrupted on-disk data can trigger that ASSERT(). [FIX] Besides the dedicated fix and the graceful exit, also let tree-checker to check such root keys, to make sure reloc trees can only exist for subvolumes.

Package Linux Kernel
Published 2025-10-07
Last modified 2026-02-05
CVSS version 3.1
Patch available
Yes

CVSS 3.1 score

5.5

out of 10
Medium
Attack Vector
Local
Attack Complexity
Low
Privileges Required
Low
User Interaction
None
Scope
Unchanged
Confidentiality
Low
Integrity
None
Availability
High
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Affected versions

Linux kernel versions 5.2.19, 5.3.4, 5.4 and later are affected. Fixed in 5.15.127, 6.1.46, 6.4.11, 6.5 and their respective stable series.

Affected from
≥ 5.2.19 ≥ 5.3.4 ≥ 5.4
Fixed in
✓ 5.15.127 5.15.x ✓ 6.1.46 6.1.x ✓ 6.4.11 6.4.x ✓ 6.5

References

The following references provide additional information about CVE-2023-53618 including vendor advisories, patch commits, exploit details, and third-party analysis. Links are sourced from the NIST NVD database.

4 patch commits total View all on NVD

Frequently asked questions

  • What is CVE-2023-53618?

    CVE-2023-53618 is a Medium severity Linux kernel vulnerability with a CVSS score of 5.5 out of 10 . It affects Linux kernel versions from 5.2.19 onward and has been patched in 5.15.127, 6.1.46, 6.4.11 and others. CVE-2023-53618 has not been confirmed as actively exploited and is not listed in the CISA KEV catalog.

  • What is the CVSS score for CVE-2023-53618?

    CVE-2023-53618 has a CVSS score of 5.5 out of 10, rated Medium severity (CVSS 3.1). The vector string is CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H .

  • Is there a patch available for CVE-2023-53618?

    Yes — CVE-2023-53618 has been patched. Fixed versions include 5.15.127, 6.1.46, 6.4.11 and others. If you are running Linux kernel 5.2.19 or later up to the fix versions, apply the relevant patch for your kernel branch.

  • Is CVE-2023-53618 actively exploited?

    No — CVE-2023-53618 has not been confirmed as actively exploited. It is not listed in the CISA Known Exploited Vulnerabilities (KEV) catalog.

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