[ CVE-2026-98132 · Published 25 Sep 2026 ]
Vulnerability in Linux
[ Description ]Official description
In the Linux kernel, the following vulnerability has been resolved: bpf: don't downgrade half-dead scalar zero spills to STACK_ZERO states.c:__clean_func_state() can downgrade scalar zero spill to STACK_ZERO in the following case: *(u64 *)(r10 - 8) = 0; ... checkpoint ... r1 = *(u32 *)(r10 - 4); ... no reads from r10-8 ... Here 4 bytes at r10-8 are dead and verifier changes scalar spill to a combination: 0000pppp (p stands for poison). Such a change breaks precision propagation chains. All places that produce STACK_ZERO should call bpf_mark_chain_precision() for the zero source. This patch fixes the bug in a simplest way possible: avoids converting stack spills of zero to STACK_ZERO. Two smarter approaches are possible: - do bpf_mark_chain_precision() from __clean_func_state() - check slot liveness information in check_stack_write_fixed_off() I investigated both and the changes required are a bit tricky, hence go with a simple fix for the time being.
[ Fixes ]Fixes and patches
- Patch on git.kernel.orgVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
- Patch on git.kernel.orgVendor patch or bulletin · NVD · Reference tagged 'Patch' by NVD
[ Advisories ]Government CERT advisories
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BSI CERT-BundWID-SEC-2026-3579
Linux Kernel: Multiple vulnerabilities Translated from German