CVE-2026-80557

CVE CVE-2026-80557EUVD EUVD-2026-66472Published 2026-08-26T14:37:24.000ZLast changed 2026-08-27T12:40:16.000ZCVSS 9.8

What the advisory describes

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 ]

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <eab3eeb68bfc639d74f27256f05546af5c4f787d; patch: 6.12.106; a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <cb8246e5846dbbe34930903a90c7a90dd8e5910b; a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <1c824e7c75bb4adf19553dd4ea944a5d83096be8; patch: 7.2; a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <7130d94846dadbb97b6b7f4d78a3a7bba6e3daa1; patch: 5.15.218; patch: 6.1.185; patch: 6.18.47; a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <f161be39201eb5f9b1f58fb8f90b8a9cd3931eb6; patch: 0; 4.9; a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <85479b7d65b4ebcb07fbbe57230976793974ab4a; patch: 7.1.10; a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <c59219a6b62d74936963983e5815524c3de8dd79; a4ed38d7a180f184a6e7aedd09db9ca4b1e6a71c <00ead17c7de137a692edee59f2772e6af687e8eb; patch: 5.10.267; patch: 6.6.154

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

Patchlage reports hits and suspected hits. About everything else this system says nothing — neither this page nor the situation report ever claims that an estate is safe.