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

Severity: medium (CVSS 5.5 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.2% probability of exploitation in the next 30 days
Public exploit or detection template: none known
Published: 2026-02-14 · updated 2026-10-19
Weakness: CWE-667

Description

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.

Affected products

Linux kernel: from 6.6 before 6.6.121; from 6.7 before 6.12.66; from 6.13 before 6.18.6; 6.19-rc1, 6.19-rc2, 6.19-rc3, 6.19-rc4 — fixed in 6.12.66, 6.18.6, 6.6.121

How to fix

Upgrade to a fixed version: Linux kernel 6.12.66, 6.18.6, 6.6.121. Check the vendor advisory for mitigations.

References

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