CVE-2026-90195riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args
Updated under an hour ago ()
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In the Linux kernel, the following vulnerability has been resolved: riscv, bpf: Fix missing sign-ext for signed 1-byte and 2-byte kfunc args On RV64, the ABI requires sign-extension for signed 1-byte and 2-byte kfunc args. However, the RV64 JIT currently does not perform sign-extension for such kfunc args. Before commit 7ce090afbf72 ("bpf: Infer zext_dst based on static register liveness analysis"), state pruning could potentially omit zero-extension of 32-bit subregisters, which inadvertently masked the above issue by making the args appear as if they had been properly sign-extended. After that commit, the problem is exposed, causing the kfunc_call/kfunc_call_test4 selftest to fail. Fix this by extending the existing sign-extension logic to handle signed 1-byte and 2-byte kfunc args as well.
- CVSS
- Not yet scored
- Weakness (CWE)
- Not given
- Known exploited
- Not in CISA's KEV catalog
- EPSS (exploitation in the next 30 days)
- Not loaded for this CVE
- Assigned by
- Linux
- NVD analysis
- Received
- Record last updated
- Oct 19, 2026
- First seen by InfoSec Signals
- Oct 9, 2026
Affected products
Linux Linux linux:linux (from the name) | 443574b033876c85a35de4c65c14f7fe092222b2 builds before 555fc6f1caf00ce7005e732b688da26c0dc3c5c5; 443574b033876c85a35de4c65c14f7fe092222b2 builds before 801ae90f8ce099187e6224cec7d72d07a4df0324; 443574b033876c85a35de4c65c14f7fe092222b2 builds before 71dbd143be598954ae103feadd12692aeb0f2f88; from 443574b033876c85a35de4c65c14f7fe092222b2 before f2aaa621591093cfe8224a25ef2f04a3b1e304b0 | CNA record |
References
- https://git.kernel.org/stable/c/555fc6f1caf00ce7005e732b688da26c0dc3c5c5
- https://git.kernel.org/stable/c/801ae90f8ce099187e6224cec7d72d07a4df0324
- https://git.kernel.org/stable/c/71dbd143be598954ae103feadd12692aeb0f2f88
- https://git.kernel.org/stable/c/f2aaa621591093cfe8224a25ef2f04a3b1e304b0
The CVE record on cve.org NVD's entry
The CVE record is authoritative. Products marked “from the name” were identified from the CNA's free-text names, not a CPE, and are matched less certainly. This product uses the NVD API but is not endorsed or certified by the NVD.