CVE-2026-98047 (GCVE-0-2026-98047)

Vulnerability from cvelistv5 – Published: 2026-09-25 10:23 – Updated: 2026-09-25 10:23
VLAI
Title
bpf: Check ancestor frames for rbtree callbacks
Summary
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.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: a44b1334aadd82203f661adb9adb41e53ad0e8d1 , < b545fa447e09e6844868deb2bee228827fe54d15 (git)
Affected: a44b1334aadd82203f661adb9adb41e53ad0e8d1 , < 2410cb2ac0416dd2795a81984c8c73d7250bd8c4 (git)
Affected: a44b1334aadd82203f661adb9adb41e53ad0e8d1 , < 369f4ce734570bdfedaa4b5ca50e2a3f6a892728 (git)
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Linux Linux Affected: 6.9
Unaffected: 0 , < 6.9 (semver)
Unaffected: 6.18.53 , ≤ 6.18.* (semver)
Unaffected: 7.2.7 , ≤ 7.2.* (semver)
Unaffected: 7.3-rc2 , ≤ * (original_commit_for_fix)
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          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Check ancestor frames for rbtree callbacks\n\nbpf_rbtree_add() invokes its comparator while the caller holds the root\nlock. The native insertion code retains raw parent and link pointers across\nthe callback, so the verifier prohibits unlocking, consuming tree nodes,\nor changing RCU state from that callback.\n\nin_rbtree_lock_required_cb() only checks the innermost verifier frame.\nStatic subprogram calls are permitted while holding a spin lock, and such a\ncall pushes a frame without in_callback_fn set. Consequently, all callback\nrestrictions disappear in the nested frame. The subprogram can unlock the\ntree, remove and drop the node being compared, then relock. Native insertion\nresumes with the stale parent pointer and links freed memory into the tree.\n\nWalk all active frames for the rbtree callback instead. Benign static\nsubprograms remain permitted, while callback restrictions follow execution\ninto nested frames."
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        "dateUpdated": "2026-09-25T10:23:57.347Z",
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          "url": "https://git.kernel.org/stable/c/369f4ce734570bdfedaa4b5ca50e2a3f6a892728"
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    "dateReserved": "2026-09-25T10:19:56.072Z",
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            "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Check ancestor frames for rbtree callbacks\n\nbpf_rbtree_add() invokes its comparator while the caller holds the root\nlock. The native insertion code retains raw parent and link pointers across\nthe callback, so the verifier prohibits unlocking, consuming tree nodes,\nor changing RCU state from that callback.\n\nin_rbtree_lock_required_cb() only checks the innermost verifier frame.\nStatic subprogram calls are permitted while holding a spin lock, and such a\ncall pushes a frame without in_callback_fn set. Consequently, all callback\nrestrictions disappear in the nested frame. The subprogram can unlock the\ntree, remove and drop the node being compared, then relock. Native insertion\nresumes with the stale parent pointer and links freed memory into the tree.\n\nWalk all active frames for the rbtree callback instead. Benign static\nsubprograms remain permitted, while callback restrictions follow execution\ninto nested frames."
          }
        ],
        "id": "CVE-2026-98047",
        "lastModified": "2026-09-25T11:17:33.553",
        "metrics": {},
        "published": "2026-09-25T11:17:33.553",
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        "vulnStatus": "Received"
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}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.



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