PT-2026-51975 · Linux · Linux

Publicado 2026-06-24 · Atualizado 2026-06-24 · CVE-2026-53081

Mitre

In the Linux kernel, the following vulnerability has been resolved:

bpf: Enforce regsafe base id consistency for BPF ADD CONST scalars

When regsafe() compares two scalar registers that both carry BPF ADD CONST, check scalar ids() maps their full compound id (aka base | BPF ADD CONST flag) as one idmap entry. However, it never verifies that the underlying base ids, that is, with the flag stripped are consistent with existing idmap mappings.

This allows construction of two verifier states where the old state has R3 = R2 + 10 (both sharing base id A) while the current state has R3 = R4 + 10 (base id C, unrelated to R2). The idmap creates two independent entries: A->B (for R2) and A|flag->C|flag (for R3), without catching that A->C conflicts with A->B. State pruning then incorrectly succeeds.

Fix this by additionally verifying base ID mapping consistency whenever BPF ADD CONST is set: after mapping the compound ids, also invoke check ids() on the base IDs (flag bits stripped). This ensures that if A was already mapped to B from comparing the source register, any ADD CONST derivative must also derive from B, not an unrelated C.

Identificadores relacionados

CVE-2026-53081

Produtos afetados

Linux

Referências · 5

• https://git.kernel.org/stable/c/691adf738817275368ed56311b7d798d617823a3 · Nota
• https://nvd.nist.gov/vuln/detail/CVE-2026-53081 · Nota de Segurança
• https://git.kernel.org/stable/c/13c02881e49aac4c82b261faa26db9edf2567231 · Nota
• https://git.kernel.org/stable/c/7d73c72cccac651acc891377a5e623e4021c6380 · Nota
• https://git.kernel.org/stable/c/2f2ec8e7730e21fc9bd49e0de9cdd58213ea24d0 · Nota