CVE-2026-98047

CVE CVE-2026-98047EUVD EUVD-2026-86700Published 2026-09-25T10:23:57.000Z

What the advisory describes

In the Linux kernel, the following vulnerability has been resolved: bpf: Check ancestor frames for rbtree callbacks bpf_rbtree_add() invokes its comparator while the caller holds the root lock. The native insertion code retains raw parent and link pointers across the callback, so the verifier prohibits unlocking, consuming tree nodes, or changing RCU state from that callback. in_rbtree_lock_required_cb() only checks the innermost verifier frame. Static subprogram calls are permitted while holding a spin lock, and such a call pushes a frame without in_callback_fn set. Consequently, all callback restrictions disappear in the nested frame. The subprogram can unlock the tree, remove and drop the node being compared, then relock. Native insertion resumes with the stale parent pointer and links freed memory into the tree. Walk all active frames for the rbtree callback instead. Benign static subprograms remain permitted, while callback restrictions follow execution into nested frames.

Source: EUVD (ENISA), in the words of the advisory.

Products the advisory names

These come from the advisory itself, not from any check we performed.

• Linux — Linux 6.9; a44b1334aadd82203f661adb9adb41e53ad0e8d1 <b545fa447e09e6844868deb2bee228827fe54d15; patch: 7.2.7; patch: 7.3-rc2; patch: 6.18.53; patch: 0; a44b1334aadd82203f661adb9adb41e53ad0e8d1 <2410cb2ac0416dd2795a81984c8c73d7250bd8c4; a44b1334aadd82203f661adb9adb41e53ad0e8d1 <369f4ce734570bdfedaa4b5ca50e2a3f6a892728

The versions shown are the advisory's own. Patchlage compares no version numbers and derives no judgement from them — which version is installed is something a person has to look up.

Carried in the product catalogue

An estate covering these products can be recorded in Patchlage. An advisory about them appears in the next morning's situation report.

• Linux — Linux

Patchlage reports hits and suspected hits. About everything else this system says nothing — neither this page nor the situation report ever claims that an estate is safe.