CVE-2026-53090
HighCVSS 7.8Exploitation Probability (EPSS)
Low risk2th percentile — higher than 2% of all known CVEs
Summary
A vulnerability was found in the Linux kernel's BPF verifier regarding ld_{abs,ind} instructions used in subprograms. On packet data load failure, the verifier did not simulate the abnormal exit path, potentially leading to incorrect control flow analysis.
Risk Assessment
Incorrect simulation of the failure path could allow execution of improperly verified BPF code, potentially leading to data integrity violations or system crashes.
Recommendation
Immediately update the Linux kernel to a version containing the fix (commit 09b28d76eac4 or later). A system reboot is required after the update.
Original NVD description (English source)
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix ld_{abs,ind} failure path analysis in subprogs Usage of ld_{abs,ind} instructions got extended into subprogs some time ago via commit 09b28d76eac4 ("bpf: Add abnormal return checks."). These are only allowed in subprograms when the latter are BTF annotated and have scalar return types. The code generator in bpf_gen_ld_abs() has an abnormal exit path (r0=0 + exit) from legacy cBPF times. While the enforcement is on scalar return types, the verifier must also simulate the path of abnormal exit if the packet data load via ld_{abs,ind} failed. This is currently not the case. Fix it by having the verifier simulate both success and failure paths, and extend it in similar ways as we do for tail calls. The success path (r0=unknown, continue to next insn) is pushed onto stack for later validation and the r0=0 and return to the caller is done on the fall-through side.