CVE-2026-80557 Affecting kernel-azure-vdso package, versions <6.12.0-160000.38.1


Severity

Recommended
high

Based on SUSE Linux Enterprise Server security rating.

Threat Intelligence

EPSS
0.53% (43rd percentile)

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  • Snyk IDSNYK-SLES1600-KERNELAZUREVDSO-20333636
  • published30 Sept 2026
  • disclosed22 Sept 2026

Introduced: 22 Sep 2026

NewCVE-2026-80557  (opens in a new tab)

How to fix?

Upgrade SLES:16.0.0 kernel-azure-vdso to version 6.12.0-160000.38.1 or higher.

NVD Description

Note: Versions mentioned in the description apply only to the upstream kernel-azure-vdso package and not the kernel-azure-vdso package as distributed by SLES. See How to fix? for SLES:16.0.0 relevant fixed versions and status.

In the Linux kernel, the following vulnerability has been resolved:

libceph: fix OOB read in decode_watchers() via missing bounds check

ceph_start_decoding() validates that struct_len bytes remain in the buffer after the encoding header, but accepts struct_len=0 as valid: ceph_decode_need(p, end, 0, bad) always passes. When a malicious or compromised OSD sends an obj_list_watch_response_t reply with struct_len=0, ceph_start_decoding() returns success with p == end, leaving zero bytes guaranteed for subsequent reads.

The immediately following ceph_decode_32(p) in decode_watchers() has no preceding bounds check. With p == end this is a 4-byte read past the validated buffer boundary. The garbage value is then passed directly to kzalloc_objs() as the watcher count.

The sibling function decode_watcher() already uses the safe variants (ceph_decode_copy_safe, ceph_decode_64_safe, ceph_decode_skip_32) after its own ceph_start_decoding() call. decode_watchers() is the only site that uses the bare variant, confirming an oversight.

Fix by replacing ceph_decode_32(p) with ceph_decode_32_safe(p, end, *num_watchers, bad), consistent with the established pattern.

Attacker model: a malicious or compromised OSD in a multi-tenant Ceph deployment (e.g. cloud) can trigger this against any kernel client that calls CEPH_OSD_OP_LIST_WATCHERS, without any further privileges beyond OSD session establishment.

[ idryomov: trim changelog ]

CVSS Base Scores

version 3.1