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Linux Kernel CVE-2026-64033

| EUVDEUVD-2026-45606 CRITICAL
2026-07-19 Linux GHSA-2qpc-f6fh-fxg4
9.8
CVSS 3.1 · Vendor: Linux
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Severity by source

Vendor (Linux) PRIMARY
9.8 CRITICAL
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
vuln.today AI
5.7 MEDIUM

Reachable only via local operation of the rtrs RDMA server under a specific setup failure, so AV:L/AC:H/PR:H; memory corruption yields integrity/availability impact with no clear confidentiality disclosure.

3.1 AV:L/AC:H/PR:H/UI:N/S:U/C:N/I:H/A:H
4.0 AV:L/AC:H/AT:P/PR:H/UI:N/VC:N/VI:H/VA:H/SC:N/SI:N/SA:N
SUSE
CRITICAL
qualitative

Primary rating from Vendor (Linux).

CVSS VectorVendor: Linux

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

5
Analysis Generated
Jul 20, 2026 - 16:59 vuln.today
CVSS changed
Jul 20, 2026 - 15:22 NVD
9.8 (CRITICAL)
Patch available
Jul 19, 2026 - 17:03 EUVD
CVE Published
Jul 19, 2026 - 15:39 cve.org
CRITICAL 9.8
CVE Published
Jul 19, 2026 - 15:39 cve.org
UNKNOWN (no severity yet)

DescriptionCVE.org

In the Linux kernel, the following vulnerability has been resolved:

RDMA/rtrs: Fix use-after-free in path file creation cleanup

In the error path of rtrs_srv_create_path_files(), the sysfs root folders may already have been created and srv_path->kobj may already have been initialized. If a later step fails, the cleanup currently calls kobject_put(&srv_path->kobj) before rtrs_srv_destroy_once_sysfs_root_folders(srv_path).

kobject_put() may drop the last reference to srv_path->kobj and invoke the release callback, rtrs_srv_release(), which frees srv_path. The following call to rtrs_srv_destroy_once_sysfs_root_folders(srv_path) then dereferences srv_path internally to access srv_path->srv, resulting in a use-after-free.

This failure path is reached before rtrs_srv_create_path_files() returns success, so the successful-path lifetime handling is not involved.

Fix this by destroying the sysfs root folders before calling kobject_put(&srv_path->kobj), so srv_path is still valid while the helper accesses it.

This issue was found by a static analysis tool I am developing.

AnalysisAI

Use-after-free in the Linux kernel's RDMA/rtrs (RDMA Transport) server module allows corruption of freed memory during the error-cleanup path of rtrs_srv_create_path_files(). When sysfs path-file creation partially fails, cleanup calls kobject_put() (which can free srv_path via the rtrs_srv_release callback) before rtrs_srv_destroy_once_sysfs_root_folders() dereferences that now-freed structure. Reported upstream by Linux/kernel maintainers with a vendor patch available; there is no public exploit identified and EPSS exploitation probability is low (0.17%, 7th percentile), consistent with a hard-to-reach error path in a niche subsystem rather than a broadly weaponizable flaw.

Technical ContextAI

The affected component is the rtrs (RDMA Transport) server, part of the Linux kernel's InfiniBand/RDMA stack that underpins the RNBD (RDMA Network Block Device) block-storage transport. The bug is an object-lifetime/reference-counting error involving the kernel kobject/sysfs model: srv_path->kobj holds a reference count, and kobject_put() may drop the final reference and synchronously invoke the release callback rtrs_srv_release(), which frees the enclosing srv_path object. The subsequent helper rtrs_srv_destroy_once_sysfs_root_folders(srv_path) then reads srv_path->srv from freed memory - a classic use-after-free (CWE-416, though the input lists CWE as N/A). The fix reorders cleanup so the root sysfs folders are destroyed while srv_path is still valid, before the kobject_put() that may free it. Per CPE data the affected product is the Linux kernel itself (cpe:2.3:a:linux:linux).

RemediationAI

Vendor-released patch: update to a fixed stable kernel - 6.18.34, 6.12.92, 6.6.142, 6.1.175, or 5.15.209 or later on the corresponding branch (fix commits include 01e42aabaf76, 548f3956e53a, 00904a73272b, 92060ab1c511, eae62c5451e6, b0e9706fb285, 5b74373390113 at git.kernel.org/stable). Apply the kernel update provided by your distribution's security channel, which backports these commits. As a compensating control where patching must be deferred, avoid loading the rtrs-server / rnbd-server modules on hosts that do not require RDMA block-storage transport (blacklist the modules or leave them unloaded); this fully removes exposure since the vulnerable code only runs when the rtrs server is active, with the trade-off of disabling RNBD/rtrs server functionality on that host. There is no in-place runtime configuration workaround for the reordering bug itself, so patching is the definitive fix.

Vendor StatusVendor

SUSE

Severity: Critical
Product Status
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise Desktop 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 15 SP7 Affected
SUSE Linux Enterprise High Availability Extension 16.0 Affected

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CVE-2026-64033 vulnerability details – vuln.today

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