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

dma-buf: dma-fence: Fix potential NULL pointer dereference

The commit mentioned in the fixes tag below introduced a mechanism
through which fence producers can fully decouple from fence consumers.
This, desirable, mechanism is based on the fence's signaled-bit as the
"decoupling point".

A sophisticated interaction between RCU and atomic instructions attempts
to ensure that fence consumers can still interact with fence producers
through the dma_fence_ops (callback pointers into the producer).

This is the desired behavior: to check for decoupling, the signaled-bit
is first checked. If it's not yet signaled, RCU ensures that the ops
pointer cannot yet be NULL.

Hereby, dma_fence_signal_timestamp_locked() first sets the signaled-bit,
and then sets the ops pointer to NULL. Readers first load the ops
pointer, and then check through the signaled-bit whether the pointer can
legally be accessed.

These set and load operations could occur out of order on weakly ordered
platforms. This problem can be solved very elegantly by using the ops
pointer itself as the synchronization point. The pointer is either NULL,
or cannot become NULL while it is being used thanks to RCU.

Replace the signaled-bit check in dma_fence_timeline_name() and
dma_fence_driver_name().
Published: 2026-08-15
Score: 5.5 Medium
EPSS: < 1% Very Low
KEV: No
Impact: n/a
Action: n/a
AI Analysis

Impact

The vulnerability originates from a race condition during DMA fence signaling in the Linux kernel. When a fence producer sets the signaled bit before a consumer clears the ops pointer, a reader may observe a NULL pointer. Dereferencing this NULL pointer results in a kernel crash, causing a denial‑of‑service at the system level.

Affected Systems

Affected systems include all Linux kernel releases that do not contain the commit that fixes the dereference. This includes the generic Linux kernel used by all distributions identified as Linux:Linux. No specific vendor version range is listed, so any kernel before the commit is vulnerable.

Risk and Exploitability

The EPSS score is below 1 % and the vulnerability is not listed in CISA’s KEV catalog, indicating a low exploitation probability. The CVSS score is 5.5, representing a medium severity. The likely attack vector requires the attacker to control a DMA fence producer or consumer and to exploit a weakly ordered memory platform to break the intended RCU synchronization. While the impact is moderate, the prerequisites make targeted exploitation unlikely at present.

Generated by OpenCVE AI on August 18, 2026 at 04:17 UTC.

Remediation

No vendor fix or workaround currently provided.

OpenCVE Recommended Actions

  • Apply the kernel patch that implements the commit fixing the NULL pointer dereference during DMA fence signaling.
  • If binary updates are not available, rebuild the kernel with the corrected commit applied and install the updated image.
  • As an interim measure, restrict or disable DMA operations that trigger fence producers/consumers, such as limiting driver access or disabling affected drivers until the patch is applied.

Generated by OpenCVE AI on August 18, 2026 at 04:17 UTC.

Tracking

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Advisories

No advisories yet.

History

Tue, 18 Aug 2026 03:45:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362

Tue, 18 Aug 2026 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Sat, 15 Aug 2026 21:30:00 +0000

Type Values Removed Values Added
Weaknesses CWE-362
CWE-476

Sat, 15 Aug 2026 06:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: dma-buf: dma-fence: Fix potential NULL pointer dereference The commit mentioned in the fixes tag below introduced a mechanism through which fence producers can fully decouple from fence consumers. This, desirable, mechanism is based on the fence's signaled-bit as the "decoupling point". A sophisticated interaction between RCU and atomic instructions attempts to ensure that fence consumers can still interact with fence producers through the dma_fence_ops (callback pointers into the producer). This is the desired behavior: to check for decoupling, the signaled-bit is first checked. If it's not yet signaled, RCU ensures that the ops pointer cannot yet be NULL. Hereby, dma_fence_signal_timestamp_locked() first sets the signaled-bit, and then sets the ops pointer to NULL. Readers first load the ops pointer, and then check through the signaled-bit whether the pointer can legally be accessed. These set and load operations could occur out of order on weakly ordered platforms. This problem can be solved very elegantly by using the ops pointer itself as the synchronization point. The pointer is either NULL, or cannot become NULL while it is being used thanks to RCU. Replace the signaled-bit check in dma_fence_timeline_name() and dma_fence_driver_name().
Title dma-buf: dma-fence: Fix potential NULL pointer dereference
First Time appeared Linux
Linux linux Kernel
CPEs cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*
Vendors & Products Linux
Linux linux Kernel
References

Subscriptions

Linux Linux Kernel
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2026-08-17T05:08:05.562Z

Reserved: 2026-08-09T03:40:39.905Z

Link: CVE-2026-72094

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Received

Published: 2026-08-15T06:21:23.477

Modified: 2026-08-17T06:18:08.327

Link: CVE-2026-72094

cve-icon Redhat

Severity : Moderate

Publid Date: 2026-08-15T00:00:00Z

Links: CVE-2026-72094 - Bugzilla

cve-icon OpenCVE Enrichment

Updated: 2026-08-18T04:30:06Z

Weaknesses