libceph: validate OSD extent maps before cursor advance
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- None · None · High
- Fix status
- Partial Red Hat: 4 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: libceph: validate OSD extent maps before cursor advance net/ceph/osd_client.c:osd_sparse_read() validates that the sparse-read data length matches the summed extent lengths, but it does not validate that each OSD-supplied extent is monotonic and lies inside the original request range. A malformed authenticated OSD reply can advertise a far-forward nonzero extent offset with a matching data length and make the client advance the message-data cursor beyond the request buffer. This reaches the BUG_ON(!*length) assertion in ceph_msg_data_next() from the client receive path. Impact: A malicious or compromised authenticated Ceph OSD peer can crash a kernel Ceph client via a malformed sparse-read reply. Reject sparse extent maps that overflow, move backwards, overlap, or extend outside the original sparse-read request before advancing the cursor. [ idryomov: perform sparse_extent_map_valid() check a bit earlier, in CEPH_SPARSE_READ_DATA_LEN instead of CEPH_SPARSE_READ_DATA_PRE state ]
Why it matters now
SSVC decision points
Not available: CISA has not published SSVC decision points for this record.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.6.157, 6.12.109, 6.18.50, 7.2.4, 7.3
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 4 | Affected | No fix yet: Fix deferred |
| Red Hat OpenShift Container Platform 5 | Affected | No fix yet: Fix deferred |
Not affected: 5 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
- Red Hat OpenShift Container Platform 4
Timeline
- 2026-10-02 Threatist record created from CVE-2026-89657
- 2026-10-03 Alias added: GHSA-9478-77xp-cr7g
- 2026-10-19 Fix available: Linux/[email protected] · CNA
- 2026-10-21 Affected versions changed · Red Hat
- 2026-10-21 CVSS score changed · Red Hat
- 2026-10-29 Affected versions changed · Red Hat
- 2026-11-06 Affected versions changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/94ae5145c520618802b0a24c047dcd5f05835db8
- https://git.kernel.org/stable/c/058ffa81f9440c5b4714685611cf697fd3739ec9
- https://git.kernel.org/stable/c/2571b35883268a266554e80d368e67fdfea7fb9d
- https://git.kernel.org/stable/c/201db408872ca12cf09e36bf0f560138c3dcfa1c
- https://git.kernel.org/stable/c/9ec08b7499a62c6d4afa93d36ab47a43fcad57d1
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Sources
- CVE-2026-89657 · CVE Program
- CVE-2026-89657 · NVD
- FIRST EPSS
- GHSA-9478-77xp-cr7g · GitHub Advisory Database · CC BY 4.0
- CVE-2026-89657 · Red Hat security data · CC BY 4.0
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