Bug 2492463 (CVE-2026-52958)

Summary: CVE-2026-52958 kernel: libceph: Fix potential out-of-bounds access in osdmap_decode()
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security <prodsec-ir-bot>
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Priority: medium    
Version: unspecifiedCC: rhel-process-autobot, watson-tool-maintainers
Target Milestone: ---Keywords: Security
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Hardware: All   
OS: Linux   
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A flaw was found in the Linux kernel's `libceph` component. This vulnerability, located within the `osdmap_decode()` function, can lead to an out-of-bounds memory access. A remote attacker could exploit this by sending a specially crafted and corrupted `osdmap` message, where the `max_osd` value exceeds the actual message content. This could potentially result in system instability or other unforeseen impacts due to memory corruption.
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Description OSIDB Bzimport 2026-06-24 18:13:26 UTC 
In the Linux kernel, the following vulnerability has been resolved:

libceph: Fix potential out-of-bounds access in osdmap_decode()

When decoding osd_state and osd_weight from an incoming osdmap in
osdmap_decode(), both are decoded for each osd, i.e., map->max_osd
times. The ceph_decode_need() check only accounts for
sizeof(*map->osd_weight) once. This can potentially result in an
out-of-bounds memory access if the incoming message is corrupted such
that the max_osd value exceeds the actual content of the osdmap message.

This patch fixes the issue by changing the corresponding part in the
ceph_decode_need() check to account for
map->max_osd*sizeof(*map->osd_weight).
Comment 1 Mauro Matteo Cascella 2026-06-25 07:50:50 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026062436-CVE-2026-52958-a72e@gregkh/T