Bug 2451168 (CVE-2026-23285)

Summary: CVE-2026-23285 kernel: drbd: fix null-pointer dereference on local read error
Product: [Other] Security Response Reporter: OSIDB Bzimport <bzimport>
Component: vulnerabilityAssignee: Product Security DevOps Team <prodsec-dev>
Status: NEW --- QA Contact:
Severity: medium Docs Contact:
Priority: medium    
Version: unspecifiedKeywords: Security
Target Milestone: ---   
Target Release: ---   
Hardware: All   
OS: Linux   
Whiteboard:
Fixed In Version: Doc Type: ---
Doc Text:
A flaw was found in the Linux kernel's Distributed Replicated Block Device (DRBD) module. A local read error within the `drbd_request_endio()` function can lead to a null-pointer dereference. This occurs when a NULL peer device is incorrectly passed to the `drbd_set_out_of_sync()` function, causing the system to crash. This vulnerability can result in a Denial of Service (DoS).
 Story Points: ---
Clone Of: Environment:
Last Closed: Type: ---
Regression: --- Mount Type: ---
Documentation: --- CRM:
Verified Versions: Category: ---
oVirt Team: --- RHEL 7.3 requirements from Atomic Host:
Cloudforms Team: --- Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-03-25 11:02:21 UTC 
In the Linux kernel, the following vulnerability has been resolved:

drbd: fix null-pointer dereference on local read error

In drbd_request_endio(), READ_COMPLETED_WITH_ERROR is passed to
__req_mod() with a NULL peer_device:

  __req_mod(req, what, NULL, &m);

The READ_COMPLETED_WITH_ERROR handler then unconditionally passes this
NULL peer_device to drbd_set_out_of_sync(), which dereferences it,
causing a null-pointer dereference.

Fix this by obtaining the peer_device via first_peer_device(device),
matching how drbd_req_destroy() handles the same situation.
Comment 1 Alexander B 2026-03-25 18:33:37 UTC 
Upstream advisory:
https://lore.kernel.org/linux-cve-announce/2026032524-CVE-2026-23285-ad41@gregkh/T