https://vulnerability.circl.lu Contains only the most 10 recent entries. http://www.rssboard.org/rss-specification python-feedgen en Tue, 29 Sep 2026 06:50:17 +0000 https://vulnerability.circl.lu/vuln/cve-2025-40143 <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>bpf: dont report verifier bug for missing bpf_scc_visit on speculative path</p> <p>Syzbot generated a program that triggers a verifier_bug() call in maybe_exit_scc(). maybe_exit_scc() assumes that, when called for a state with insn_idx in some SCC, there should be an instance of struct bpf_scc_visit allocated for that SCC. Turns out the assumption does not hold for speculative execution paths. See example in the next patch.</p> <p>maybe_scc_exit() is called from update_branch_counts() for states that reach branch count of zero, meaning that path exploration for a particular path is finished. Path exploration can finish in one of three ways: a. Verification error is found. In this case, update_branch_counts() is called only for non-speculative paths. b. Top level BPF_EXIT is reached. Such instructions are never a part of an SCC, so compute_scc_callchain() in maybe_scc_exit() will return false, and maybe_scc_exit() will return early. c. A checkpoint is reached and matched. Checkpoints are created by is_state_visited(), which calls maybe_enter_scc(), which allocates bpf_scc_visit instances for checkpoints within SCCs.</p> <p>Hence, for non-speculative symbolic execution paths, the assumption still holds: if maybe_scc_exit() is called for a state within an SCC, bpf_scc_visit instance must exist.</p> <p>This patch removes the verifier_bug() call for speculative paths.</p> <p><strong>Affected:</strong> Linux</p> <p>In the Linux kernel, the following vulnerability has been resolved:</p> <p>bpf: dont report verifier bug for missing bpf_scc_visit on speculative path</p> <p>Syzbot generated a program that triggers a verifier_bug() call in maybe_exit_scc(). maybe_exit_scc() assumes that, when called for a state with insn_idx in some SCC, there should be an instance of struct bpf_scc_visit allocated for that SCC. Turns out the assumption does not hold for speculative execution paths. See example in the next patch.</p> <p>maybe_scc_exit() is called from update_branch_counts() for states that reach branch count of zero, meaning that path exploration for a particular path is finished. Path exploration can finish in one of three ways: a. Verification error is found. In this case, update_branch_counts() is called only for non-speculative paths. b. Top level BPF_EXIT is reached. Such instructions are never a part of an SCC, so compute_scc_callchain() in maybe_scc_exit() will return false, and maybe_scc_exit() will return early. c. A checkpoint is reached and matched. Checkpoints are created by is_state_visited(), which calls maybe_enter_scc(), which allocates bpf_scc_visit instances for checkpoints within SCCs.</p> <p>Hence, for non-speculative symbolic execution paths, the assumption still holds: if maybe_scc_exit() is called for a state within an SCC, bpf_scc_visit instance must exist.</p> <p>This patch removes the verifier_bug() call for speculative paths.</p> https://vulnerability.circl.lu/vuln/cve-2025-40143