In the Linux kernel, the following vulnerability has been resolved:
futex: Avoid private hash use-after-free on final put
futex_private_hash_put() drops the reference to fph before evaluating
fph->mm for wake_up_var(). futex_ref_put() enables preemption again before
returning. If that put drops the final reference and the task is preempted,
another task can pivot to the replacement hash and free the old hash after
an RCU grace period. The first task then reads fph->mm from the freed
allocation when it resumes.
KASAN reports a slab-use-after-free in futex_private_hash_put(), with the
read at offset 24 in a freed kmalloc-512 allocation. The allocation and
free stacks point to futex_hash_allocate() and the RCU free path,
respectively.
Load the mm pointer while the fph reference is still held and pass the
saved value to wake_up_var(). wake_up_var() uses the pointer as a waitqueue
key and does not dereference the mm through it.
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 2026-10-24). 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