CVE-2026-43408

HIGH EPSS 2.9%
Published May 8, 20261mo ago · Modified Jun 17, 20262w ago
7.8 CVSS 3.1
High
Find Similar
Published May 8, 2026 1mo ago
Last Modified Jun 17, 2026 2w ago

Description

In the Linux kernel, the following vulnerability has been resolved: ceph: add a bunch of missing ceph_path_info initializers ceph_mdsc_build_path() must be called with a zero-initialized ceph_path_info parameter, or else the following ceph_mdsc_free_path_info() may crash. Example crash (on Linux 6.18.12): virt_to_cache: Object is not a Slab page! WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6732 kmem_cache_free+0x316/0x400 [...] Call Trace: [...] ceph_open+0x13d/0x3e0 do_dentry_open+0x134/0x480 vfs_open+0x2a/0xe0 path_openat+0x9a3/0x1160 [...] cache_from_obj: Wrong slab cache. names_cache but object is from ceph_inode_info WARNING: CPU: 184 PID: 2871736 at mm/slub.c:6746 kmem_cache_free+0x2dd/0x400 [...] kernel BUG at mm/slub.c:634! Oops: invalid opcode: 0000 [#1] SMP NOPTI RIP: 0010:__slab_free+0x1a4/0x350 Some of the ceph_mdsc_build_path() callers had initializers, but others had not, even though they were all added by commit 15f519e9f883 ("ceph: fix race condition validating r_parent before applying state"). The ones without initializer are suspectible to random crashes. (I can imagine it could even be possible to exploit this bug to elevate privileges.) Unfortunately, these Ceph functions are undocumented and its semantics can only be derived from the code. I see that ceph_mdsc_build_path() initializes the structure only on success, but not on error. Calling ceph_mdsc_free_path_info() after a failed ceph_mdsc_build_path() call does not even make sense, but that's what all callers do, and for it to be safe, the structure must be zero-initialized. The least intrusive approach to fix this is therefore to add initializers everywhere.

CVSS Details

Base Score
7.8
Exploitability
1.8
Impact
5.9
Vector string
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Attack Vector Local
Attack Complexity Low
Privileges Required Low
User Interaction None
Scope Unchanged
Confidentiality High
Integrity High
Availability High

Threat Intelligence

EPSS Exploit Probability
2.9% percentile
Exploit & Patch Status
No Known Exploit
Patch Available

Weaknesses 1

CWE-476 NULL Pointer Dereference Memory Safety

Affected Products 10

VendorProductVersionRange
linuxlinux_kernel*≥6.12.48  –  <6.12.78
linuxlinux_kernel*≥6.16.8  –  <6.17
linuxlinux_kernel*≥6.17.1  –  <6.18.19
linuxlinux_kernel*≥6.19  –  <6.19.9
linuxlinux_kernel6.17any
linuxlinux_kernel6.17any
linuxlinux_kernel6.17any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any
linuxlinux_kernel7.0any

References 4

  • git.kernel.org https://git.kernel.org/stable/c/43323a5934b660afae687e8e4e95ac328615a5c4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/453df1f4535842bf17ff1885a225e153d7ee3374
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/644b47f0574fd82aeb9d00317eca8d1f2a525c8c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8be8911f590813e6f90bc6407ced1b23e50bc5da
    Patch

Remediation

  • git.kernel.org https://git.kernel.org/stable/c/43323a5934b660afae687e8e4e95ac328615a5c4
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/453df1f4535842bf17ff1885a225e153d7ee3374
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/644b47f0574fd82aeb9d00317eca8d1f2a525c8c
    Patch
  • git.kernel.org https://git.kernel.org/stable/c/8be8911f590813e6f90bc6407ced1b23e50bc5da
    Patch