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CVE Record

CVE-2026-23136: libceph: reset sparse-read state in osd_fault()

In the Linux kernel, the following vulnerability has been resolved: libceph: reset sparse-read state in osd_fault() When a fault occurs, the connection is abandoned, reestablished, and any pending operations are retried. The OSD client tracks the progress of a sparse-read reply using a separate state machine, largely independent of the messenger's state. If a connection is lost mid-payload or the sparse-read state machine returns an error, the sparse-read state is not reset. The OSD client will then interpret the beginning of a new reply as the continuation of the old one. If this makes the sparse-read machinery enter a failure state, it may never recover, producing loops like: libceph: [0] got 0 extents libceph: data len 142248331 != extent len 0 libceph: osd0 (1)...:6801 socket error on read libceph: data len 142248331 != extent len 0 libceph: osd0 (1)...:6801 socket error on read Therefore, reset the sparse-read state in osd_fault(), ensuring retries start from a clean state.

HighCVSS 7.5Not KEV-listedUpdated
Glexia's TakeAutomated analysishigh

Security readout for executives and security teams

Plain-English summary

A Linux Ceph storage client can become stuck after a connection failure interrupts a sparse read. Retried reads may be mistaken for continuations of the failed reply, causing recurring errors and loss of storage availability. The supplied CVSS score is 7.5, reflecting high availability impact without identified confidentiality or integrity impact.

Executive priority

Treat as high priority for production systems whose services depend on Linux Ceph client availability. Expedite verification and patching where a storage-client failure could interrupt critical workloads. Lower the priority for systems that do not use libceph or where the applicable stable fix is already confirmed.

Technical view

libceph maintains sparse-read progress separately from messenger connection state. Before the fix, osd_fault() did not reset that progress after connection loss or sparse-read errors. A retried operation could therefore parse a new reply using stale state, enter a persistent failure condition, and repeatedly encounter length mismatches and socket read errors. The fix resets sparse-read state before retrying.

Likely exposure

Exposure is most relevant to systems using the Linux libceph OSD client for Ceph sparse-read operations on affected kernels. A connection fault during reply processing is required for the described failure. The supplied version data is ambiguous, so kernel build and patch status should be verified directly rather than inferred solely from version numbers.

Exploitation context

The supplied CVSS vector describes network reachability, low complexity, no privileges, no user interaction, and availability-only impact. However, the sources do not establish active exploitation, public exploit availability, or inclusion in CISA KEV. They also do not demonstrate that arbitrary internet clients can trigger the condition.

Researcher notes

The failure is a retry-state synchronization defect, not evidence of data disclosure or modification. Useful investigation should focus on branch-specific fix ancestry, sparse-read usage, connection-fault timing, and whether clients recover after faults. The provided affected-version list contains unclear entries and should not be treated as a complete distribution-level applicability statement.

Mitigation direction

  • Apply the applicable Linux stable fix referenced for the deployed kernel branch.
  • Obtain distribution-specific kernel guidance when commit inclusion cannot be confirmed.
  • Prioritize Ceph clients supporting availability-sensitive storage workloads.
  • Use operational redundancy while affected clients await remediation.

Validation and detection

  • Inventory Linux hosts using libceph as Ceph OSD clients.
  • Record kernel versions and confirm inclusion of an applicable referenced fix.
  • Review kernel logs for repeated sparse-read length mismatches and OSD socket read errors.
  • Test connection-fault recovery only in a controlled staging environment.
Prepared
Confidence
medium
Sources
6

Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.

Potential ATT&CK relevance

Conservative CVE-to-ATT&CK context

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CVE-2026-23136 mapping review

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Vulnerability profileCVE Program record
Severity
High
CVSS
7.5 (3.1)
Known Exploited
No
Published

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Official CVE source material

CNA and ADP enrichment extracted from CVE v5

These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.

1CVSS vectors
3Timeline events
0ADP providers
5Source links

CVSS vector scores

1 official score

We collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.

ScoreVersionSeverityVectorExploitImpactSource
7.5CVSS 3.1HighCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H3.93.6Linux

Vulnerability scoring details

Base CVSS 3.1 score

7.5High
CVSS 3.1 vector shape for CVE-2026-23136Attack VectorAttack ComplexityPrivileges RequiredUser InteractionScopeConfidentiality ImpactIntegrity ImpactAvailability Impact

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Attack Vector
NetworkAdjacentLocalPhysical
Attack Complexity
LowHigh
Privileges Required
NoneLowHigh
User Interaction
NoneRequired
Scope
ChangedUnchanged
Confidentiality Impact
HighLowNone
Integrity Impact
HighLowNone
Availability Impact
HighLowNone

Vulnerability timeline

Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.

  1. CVE reservedCVE Program

    The CVE ID was reserved by the assigning CNA.

  2. CVE publishedCVE Program

    The CVE record was published.

  3. CVE updatedCVE Program

    The CVE record metadata indicates this as the latest update time.

Affected products

Products and packages named in the record

VendorProductVersion / packageStatus
LinuxLinuxf628d799972799023d32c2542bb2639eb8c4f84e, f628d799972799023d32c2542bb2639eb8c4f84e, f628d799972799023d32c2542bb2639eb8c4f84e, f628d799972799023d32c2542bb2639eb8c4f84eunaffected
LinuxLinux6.6, 0, 6.6.121, 6.12.66, 6.18.6, 6.19affected
Weakness

CWE details

No CWE listed

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