CVE-2026-98034: Linux

EPSS: 0.2% chance of exploitation in the next 30 days.

In the Linux kernel, the following vulnerability has been resolved: bpf: Mark NULL kptr stores precise check_map_kptr_access() permits a scalar store into an untrusted kptr field only when the register is known to contain zero. Unlike other verifier checks whose outcome depends on a scalar value, it does not mark that register precise. A state checkpoint reached with an imprecise zero can therefore prune a second path that reaches the store with an arbitrary nonzero scalar. The program can write attacker-controlled bits into the kptr field and load them back as a PTR_TO_BTF_ID. Call mark_chain_precision() before accepting a known-zero register. This forces state equivalence to compare its scalar range and makes the verifier visit and reject a path carrying a nonzero value.

Affected products

• Linux Linux: from 5.18.18, before 5.19 (fixed in 5.19); from 5.19, before 7.2.7 (fixed in 7.2.7)

Published 2026-09-25. Last modified 2026-09-25.