Kernel use-after-free via lost inner-map identity
Published Sep 25, 2026 · Updated Sep 25, 2026
Use-after-free in Linux 5.13 allows attackers to trigger a stale map dereference through nested BPF map callbacks. Callback-frame constructors clear map_uid while restoring map_ptr, causing distinct inner maps with one template to appear identical and letting bpf_timer_init pair a timer with the wrong map. The sequence requires crafted nested BPF callbacks; published material does not establish whether the resulting kernel use-after-free causes a crash, privilege escalation, or code execution.
Summary
What happened
Use-after-free in Linux 5.13 allows attackers to trigger a stale map dereference through nested BPF map callbacks. Callback-frame constructors clear map_uid while restoring map_ptr, causing distinct inner maps with one template to appear identical and letting bpf_timer_init pair a timer with the wrong map. The sequence requires crafted nested BPF callbacks; published material does not establish whether the resulting kernel use-after-free causes a crash, privilege escalation, or code execution.
The record
- CVE
- CVE-2026-98033
- Published
- Sep 25, 2026
- Updated
- Sep 25, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- Unavailable
- Attack vector
- Unavailable
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 25, 2026CVE publishedPublication date reported by the CVE source.
- Sep 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=5.13
- Affected versionversion=69c087ba6225b574afb6e505b72cb75242a3d844 <66ff2eff093d2a0838f39c713eeb590bc0946c2a
- Affected versionversion=69c087ba6225b574afb6e505b72cb75242a3d844 <b90c5d770dad910fb89e6c1b15052a8a1e8db752
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Activity data is delayed. The latest report is Sep 28, 2026.
Weakness, pattern, technique
No sourced classifications are available.
Public exploit references
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Technologies
Your stack
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Your stack
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