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Out-of-bounds Read The advisory has been revoked - it doesn't affect any version of package rhcos  (opens in a new tab)

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  • Snyk IDSNYK-RHEL8-RHCOS-18678947
  • published12 Aug 2026
  • disclosed10 Aug 2026
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Introduced: 10 Aug 2026

CVE-2026-68160  (opens in a new tab)
CWE-125  (opens in a new tab)

Amendment

The Red Hat security team deemed this advisory irrelevant for RHEL:8.

NVD Description

Note: Versions mentioned in the description apply only to the upstream rhcos package and not the rhcos package as distributed by RHEL.

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

ceph: fix pre-auth out-of-bounds read on snaptrace in ceph_handle_caps()

ceph_handle_caps() reads snap_trace_len from the wire-format ceph_mds_caps header and uses it unconditionally to build a fake end pointer (snaptrace + snaptrace_len) that is later handed to ceph_update_snap_trace() in the CEPH_CAP_OP_IMPORT case:

snaptrace     = h + 1;
snaptrace_len = le32_to_cpu(h->snap_trace_len);
p             = snaptrace + snaptrace_len;
...
case CEPH_CAP_OP_IMPORT:
    if (snaptrace_len) {
        ...
        if (ceph_update_snap_trace(mdsc, snaptrace,
                                   snaptrace + snaptrace_len,
                                   false, &realm)) { ... }

ceph_update_snap_trace() then decodes a struct ceph_mds_snap_realm from snaptrace using ceph_decode_need(&p, e, sizeof(*ri), bad) with the attacker-supplied fake end e == snaptrace + snaptrace_len. With snaptrace_len == 0xFFFFFFFF the bound check is trivially satisfied, ri = p reads sizeof(struct ceph_mds_snap_realm) past the legitimate msg->front buffer, and ri->num_snaps / ri->num_prior_parent_snaps then drive further out-of-bounds reads of the encoded snap arrays.

The eleven msg_version >= 2 .. msg_version >= 12 decoder blocks above the op switch each catch this OOB through their ceph_decode_*_safe() / ceph_decode_need() helpers, but they sit behind a hdr.version-gated if, so a malicious or compromised MDS that sets msg->hdr.version = 1 reaches the IMPORT path with no version-gated decoder having validated snap_trace_len. The shape has been present since ceph_handle_caps() was introduced.

Validate snap_trace_len against the message front buffer before consuming it, using the canonical ceph_decode_need() / ceph_has_room() helper. The helper bounds the length with subtraction (n <= end - p, guarded by end >= p) rather than pointer addition, so it is wrap-safe for the attacker-controlled u32 length on 32-bit builds where p + snap_trace_len could overflow the address space. This matches the rest of the ceph decode path (e.g. the pool_ns_len check a few lines below), and the existing goto bad cleanup already covers this exit path.