bpf: Clear rb node linkage when freeing bpf_rb_root
Key facts
- Attack vector
- Local
- Privileges required
- Low
- User interaction
- None
- Attack complexity
- Low
- Impact type
- —
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Partial Red Hat: 2 without a fix
Attack profile from CVSS 3.1 · CNA. Fix status from CNA and Red Hat.
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Clear rb node linkage when freeing bpf_rb_root bpf_rb_root_free() detaches the root by copying the current rb_root_cached and then replacing the live root with RB_ROOT_CACHED. It then walks the copied root and drops each object contained in the tree. This leaves the rb node state intact while dropping the object. If the object is refcounted and survives the drop, its bpf_rb_node_kern still contains an owner pointer to the freed root and stale rb tree linkage. If a later bpf_rb_root allocation reuses the same address, bpf_rbtree_remove() can incorrectly pass the owner check and call rb_erase_cached() on a node whose rb pointers belong to the old tree. Mirror the list draining behavior by marking nodes as busy while the root is being detached, then clear the rb node and release the owner before dropping the containing object. This makes surviving nodes unowned and safe to reject from remove or accept for a later add.
Why it matters now
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
Remediation
- Fix · CNA Linux (Linux) Fixed in 6.3
- Fix · CNA Linux (Linux) Fixed in 6.6.160, 6.12.114, 6.18.40, 7.1.5, 7.2
Vendor assessments
Red Hat
Red Hat rating: Moderate. Red Hat's page for this CVE →
| Product | Status | Plan or fix |
|---|---|---|
| Red Hat Enterprise Linux 10 | Affected | No fix yet: Fix deferred |
| Red Hat Enterprise Linux 9 | Affected | No fix yet: Fix deferred |
Not affected: 4 products
- Red Hat Enterprise Linux 6
- Red Hat Enterprise Linux 7
- Red Hat Enterprise Linux 8
- Red Hat Enterprise Linux 9
Timeline
- 2026-10-02 Threatist record created from CVE-2026-74344
- 2026-10-03 Alias added: GHSA-345m-8q8p-cx77
- 2026-10-16 CISA SSVC decision points changed
- 2026-10-21 Fix available: Linux/[email protected], Linux/[email protected], Linux/Linux@628a469d2a73e3844e5ee80aa002e232b0fd6493 +1 · CNA
- 2026-10-21 2 new references · CNA
- 2026-10-29 Affected versions changed · Red Hat
- 2026-10-30 CVSS score changed · Red Hat
References
Other 5
- https://git.kernel.org/stable/c/628a469d2a73e3844e5ee80aa002e232b0fd6493
- https://git.kernel.org/stable/c/ff3ab3fb956027ab40aca1fb3298cf20dc290273
- https://git.kernel.org/stable/c/2eb39de4962f842d653e96818ae372665cd481fd
- https://git.kernel.org/stable/c/574612793bed416f6c05fe7c9b50e9eb0441997e
- https://git.kernel.org/stable/c/4a7910ee060d8ce55612f5b3cc267f3a265a3cec
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Sources
- CVE-2026-74344 · CVE Program
- CVE-2026-74344 · NVD
- FIRST EPSS
- GHSA-345m-8q8p-cx77 · GitHub Advisory Database · CC BY 4.0
- CVE-2026-74344 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences