Kernel soft lockup via stale BPF jump offset
Published Sep 16, 2026 · Updated Sep 16, 2026
Incorrect branch offsets in the LoongArch BPF JIT in Linux allow local users to cause kernel soft lockups through crafted tail-call programs. The emit_bpf_tail_call function derives branch distances from a stale prior-pass code stride, so extra JIT passes can target misaligned instruction boundaries. Reachability requires a LoongArch system, BPF JIT compilation, and a tail-call program; BPF loading privileges depend on the unprivileged-BPF setting.
Summary
What happened
Incorrect branch offsets in the LoongArch BPF JIT in Linux allow local users to cause kernel soft lockups through crafted tail-call programs. The emit_bpf_tail_call function derives branch distances from a stale prior-pass code stride, so extra JIT passes can target misaligned instruction boundaries. Reachability requires a LoongArch system, BPF JIT compilation, and a tail-call program; BPF loading privileges depend on the unprivileged-BPF setting.
The record
- CVE
- CVE-2026-89906
- Published
- Sep 16, 2026
- Updated
- Sep 16, 2026
- Vendor
- The Linux Kernel Organization
- Product
- Linux
- Classifications
- T1499.004
- Attack vector
- local
- Privileges
- Unavailable
Timeline
How it unfolded
- Sep 16, 2026CVE publishedPublication date reported by the CVE source.
- Sep 16, 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?
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- Affected versionversion=17c010fe45def335fe03a0718935416b04c7f349
- Affected versionversion=1a782fa32e644aa9fbae6c8488f3e61221ac96e1
- Affected versionversion=6.1.149 <6.2
- Affected versionversion=6.12.43 <6.13
- Affected versionversion=6.15.11 <6.16
- Affected versionversion=6.16.2 <6.17
- Affected versionversion=6.17
- Affected versionversion=6.6.103 <6.7
- Affected versionversion=9262e3e04621558e875eb5afb5e726b648cd5949
- Affected versionversion=cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3 <37d545d12f21c4d50612ecaebd7ae1e5bf91b2d8
- Affected versionversion=cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3 <882b8912b7e92341fdb115ba0e2e5142a28684ff
- Affected versionversion=cd39d9e6b7e4c58fa77783e7aedf7ada51d02ea3 <96f44d493c280ea161569c43d7ed0f3b0815803a
- Affected versionversion=f2b5e50cc04d7a049b385bc1c93b9cbf5f10c94f
- Affected versionversion=f83d469e16bb1f75991ca67c56786fb2aaa42bea
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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