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().
What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)
- EG Severity
- Not assessed: no CVSS publishedA missing CVSS is not a severity of zero.
- EG Likelihood
- 0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-17). FIRST's exploitation probability, not an EchelonGraph model.
- Confirmed exploitation
- None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
- EG Priority
- No SSVC decision: EchelonGraph has not assessed this CVECISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source: the BOD 26-04 block below.
BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; Fix on system upgrade if it is not.
In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA's BOD 26-04 default) · Technical impact total (CISA's BOD 26-04 default). Where an input reads “CISA's BOD 26-04 default”, no one has published it for this CVE, and CISA's implementation guidance says: “If “Automatable” and “Technical Impact” information items about a CVE ID are not available and the CVE ID is not in the KEV Catalog, CISA will treat its values as “no” and “total,” respectively, until CISA or a third party provides metadata about the CVE ID. CISA will always provide the Vulnrichment data for a CVE ID listed in the KEV Catalog.” Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it