{"cve":"CVE-2026-98034","nvd":{"published":"2026-09-25T11:17:32.123","modified":"2026-10-21T13:21:19.607","status":"Received","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Mark NULL kptr stores precise\n\ncheck_map_kptr_access() permits a scalar store into an untrusted kptr\nfield only when the register is known to contain zero. Unlike other\nverifier checks whose outcome depends on a scalar value, it does not mark\nthat register precise.\n\nA state checkpoint reached with an imprecise zero can therefore prune a\nsecond path that reaches the store with an arbitrary nonzero scalar. The\nprogram can write attacker-controlled bits into the kptr field and load\nthem back as a PTR_TO_BTF_ID.\n\nCall mark_chain_precision() before accepting a known-zero register. This\nforces state equivalence to compare its scalar range and makes the verifier\nvisit and reject a path carrying a nonzero value.","cvss_v4":null,"cvss_v3":null,"cwes":[],"references":["https://git.kernel.org/stable/c/86168208737bdd267d92d855d453d1d2f840df19","https://git.kernel.org/stable/c/86a3171c90bfc35a54e9d83cd197ca0d72d2f4e4","https://git.kernel.org/stable/c/b8b98d3d37908402ff63515fa4d7574235436ea8","https://git.kernel.org/stable/c/bb667eb575c906f24c707986541a99424c5b07ea","https://git.kernel.org/stable/c/ecdc5043794c9184aa8e6c814603899479c46b35"],"products":[],"source":"nvd","synced_at":"2026-10-22T16:41:11.231219466+00:00"},"epss":{"cve":"CVE-2026-98034","score":0.002,"percentile":0.09801,"date":"2026-10-25"},"kev":null,"osv":[],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}