Vulnerability in Linux kernel (CVE-2026-89657)
Summary
Vulnerability in Linux kernel (CVE-2026-89657). Risk of unauthorized operations or information disclosure.
Original description
The description as published by the source.
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 ]
Source: NIST National Vulnerability Database NVD GitHub Advisory
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2026-89657 has been found in Linux kernel.
Risk of unauthorized operations or information disclosure. CVSS score: 7.5/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2026-89657" on the vendor's site.
CVE-2026-89657 (Linux kernel) — CVSS v3 7.5
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
A vulnerability (unclassified) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.5/10). Risk of unauthorized operations or information disclosure.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Ubuntu UBUNTU-CVE-2026-89657 linux-hwe-edge
References
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web git.kernel.org
- web nvd.nist.gov
- web github.com