In the Linux kernel, the following vulnerability has been resolved:
scsi: ufs: core: Fix data race in CPU latency PM QoS request handling
The cpu_latency_qos_add/remove/update_request interfaces lack internal
synchronization by design, requiring the caller to ensure thread safety.
The current implementation relies on the 'pm_qos_enabled' flag, which is
insufficient to prevent concurrent access and cannot serve as a proper
synchronization mechanism. This has led to data races and list
corruption issues.
A typical race condition call trace is:
[Thread A]
ufshcd_pm_qos_exit()
--> cpu_latency_qos_remove_request()
--> cpu_latency_qos_apply();
--> pm_qos_update_target()
--> plist_del <--(1) delete plist node
--> memset(req, 0, sizeof(*req));
--> hba->pm_qos_enabled = false;
[Thread B]
ufshcd_devfreq_target
--> ufshcd_devfreq_scale
--> ufshcd_scale_clks
--> ufshcd_pm_qos_update <--(2) pm_qos_enabled is true
--> cpu_latency_qos_update_request
--> pm_qos_update_target
--> plist_del <--(3) plist node use-after-free
Introduces a dedicated mutex to serialize PM QoS operations, preventing
data races and ensuring safe access to PM QoS resources, including sysfs
interface reads.
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. 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, and whom BOD 26-04 binds: 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.
The score's inputs: 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