CVE-2026-43405
In the Linux kernel, the following vulnerability has been resolved: libceph: Use u32 for non-negative values in ceph_monmap_decode() This patch fixes unnecessary implicit conversions that change signedness of blob_len and num_mon in ceph_monmap_decode().
Does this matter?
High impact if exploited, but EPSS currently rates exploitation as unlikely (0.49%). Schedule it in the normal patch cycle and watch for a rise in EPSS or a public exploit.
Description
In the Linux kernel, the following vulnerability has been resolved: libceph: Use u32 for non-negative values in ceph_monmap_decode() This patch fixes unnecessary implicit conversions that change signedness of blob_len and num_mon in ceph_monmap_decode(). Currently blob_len and num_mon are (signed) int variables. They are used to hold values that are always non-negative and get assigned in ceph_decode_32_safe(), which is meant to assign u32 values. Both variables are subsequently used as unsigned values, and the value of num_mon is further assigned to monmap->num_mon, which is of type u32. Therefore, both variables should be of type u32. This is especially relevant for num_mon. If the value read from the incoming message is very large, it is interpreted as a negative value, and the check for num_mon > CEPH_MAX_MON does not catch it. This leads to the attempt to allocate a very large chunk of memory for monmap, which will most likely fail. In this case, an unnecessary attempt to allocate memory is performed, and -ENOMEM is returned instead of -EINVAL.
- CVSS 3.1
- 7.5 HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
- EPSS
- 0.49% probability · 41th percentile
- CISA KEV
- Not listed
- Weakness
- CWE-908
- Affected
- linux/linux kernel
- Source
- 416baaa9-dc9f-4396-8d5f-8c081fb06d67
References
- https://git.kernel.org/stable/c/08bc6173fd611ad5a40f472bf5f15b92aea0fe40Patch
- https://git.kernel.org/stable/c/5f2806684b05bd24d05c091083b8e2517ba8ffacPatch
- https://git.kernel.org/stable/c/770444611f047dbfd4517ec0bc1b179d40c2f346Patch
- https://git.kernel.org/stable/c/86f7060cd638d6eb042e8ed780fb83a59ca0dcb3Patch
- https://git.kernel.org/stable/c/b268984ae88cb0dcd7a8e8263962c748448e26e8Patch
- https://git.kernel.org/stable/c/ba0a4df8c563536857dcbf7b4dbd0f2a15f57acePatch
- https://git.kernel.org/stable/c/ee5588e2bc41acb73f6676c0520420c107cd0140Patch
Source: NVD record, EPSS from FIRST.org, KEV from CISA. Refreshed daily.