Vulnerability in Linux

[ Description ]Official description

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.

[ Fixes ]Fixes and patches

No fix or interim patch is linked from our sources yet. Check the vendor references below and limit exposure of affected systems until a fix is available.

[ Advisories ]Government CERT advisories

• BSI CERT-Bund24 Sep 2026WID-SEC-2026-3579

  Linux Kernel: Multiple vulnerabilities Translated from German

  CVE-2026-97615CVE-2026-97978CVE-2026-98127+590 more CVEs

[ References ]References

• git.kernel.org/stable/c/86168208737bdd267d92d855d453d1d2f840df19
• git.kernel.org/stable/c/86a3171c90bfc35a54e9d83cd197ca0d72d2f4e4
• git.kernel.org/stable/c/b8b98d3d37908402ff63515fa4d7574235436ea8
• git.kernel.org/stable/c/bb667eb575c906f24c707986541a99424c5b07ea
• git.kernel.org/stable/c/ecdc5043794c9184aa8e6c814603899479c46b35