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CVE-2025-37797 is a use-after-free vulnerability in the Linux kernel's HFSC queueing discipline class-handling logic. In hfsc_change_class(), an initial check establishes that a class queue contains packets before qdisc_peek_len() is called. Certain child queueing disciplines, including codel and netem, can drop packets during that call and empty the queue. The vulnerable code nevertheless inserts the class into vttree, violating the scheduler's invariant that the tree contains only non-empty classes. Subsequent destruction of the class can result in use-after-free. The fix rechecks the queue length after qdisc_peek_len() before proceeding.
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A use-after-free vulnerability in the Linux kernel's HFSC queueing discipline. Certain child queueing disciplines can empty a queue during qdisc_peek_len(), after an initial queue-length check. The code incorrectly assumes the queue remains nonempty and adds the class to vttree, potentially causing use-after-free when the class is destroyed. The listed CVSS v3 score is 7.8, with local access and low privileges required and potentially high confidentiality, integrity, and availability impacts. The fix rechecks queue length after qdisc_peek_len().
A use-after-free vulnerability in Linux kernel net_sched HFSC class handling.
A use-after-free vulnerability in Linux kernel net_sched HFSC class handling. The plugin's CVSS information is sourced from this CVE.
A high-severity local Linux kernel use-after-free flaw in the HFSC network scheduler's class handling. The issue can occur when queue state changes during processing of child qdiscs such as netem or codel, violating scheduler assumptions and leading to use-after-free on class destruction.
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Cross-references every affected SKU, including bundled OEM variants.
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