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CVE-2026-98034

bpf: Mark NULL kptr stores precise PUBLISHED

Description (CNA)

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 (CNA)

Vendor / productVersions
Linux / Linuxaffected 61df10c7799e27807ad5e459eec9d77cddf8bf45 before 86a3171c90bfc35a54e9d83cd197ca0d72d2f4e4; affected 61df10c7799e27807ad5e459eec9d77cddf8bf45 before b8b98d3d37908402ff63515fa4d7574235436ea8; affected 61df10c7799e27807ad5e459eec9d77cddf8bf45 before bb667eb575c906f24c707986541a99424c5b07ea; affected 61df10c7799e27807ad5e459eec9d77cddf8bf45 before 86168208737bdd267d92d855d453d1d2f840df19; affected 61df10c7799e27807ad5e459eec9d77cddf8bf45 before ecdc5043794c9184aa8e6c814603899479c46b35; affected b5a8069835e5236824a84281592d29f859b33153; affected 5.18.18 before 5.19
Linux / Linuxaffected 5.19; unaffected 0 before 5.19; unaffected 6.6.160 through 6.6.*; unaffected 6.12.114 through 6.12.*; unaffected 6.18.57 through 6.18.*; unaffected 7.2.7 through 7.2.*; unaffected 7.3 through *

CWE

No CWE identifiers supplied.

References