{"id":"CVE-2023-52928","title":"bpf: Skip invalid kfunc call in backtrack_insn","summary":"In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Skip invalid kfunc call in backtrack_insn\n\nThe verifier skips invalid kfunc call in check_kfunc_call(), which\nwould be captured in fixup_kfunc_call() if such insn …","severity":"none","vendor":"Linux","product":"Linux","affected":["Linux >= e6ac2450d6dee3121cd8bbf2907b78a68a8a353d < 6e2fac197de2c4c041bdd8982cffb104689113f1","Linux >= e6ac2450d6dee3121cd8bbf2907b78a68a8a353d < 74eec8266f37aff609db6a2f2b093e56a11c28c4","Linux >= e6ac2450d6dee3121cd8bbf2907b78a68a8a353d < d3178e8a434b58678d99257c0387810a24042fb6","Linux 5.13"],"ssvc":{"exploitation":"none","automatable":"no","technicalImpact":"partial","timestamp":"2026-11-05T20:13:55.097270Z"},"published":"2025-03-27","updated":"2026-11-05","sourceUpdated":"2026-11-05T20:20:52.893Z","source":"CVEORG","sourceUrl":"https://www.cve.org/CVERecord?id=CVE-2023-52928","references":[{"url":"https://git.kernel.org/stable/c/6e2fac197de2c4c041bdd8982cffb104689113f1"},{"url":"https://git.kernel.org/stable/c/74eec8266f37aff609db6a2f2b093e56a11c28c4"},{"url":"https://git.kernel.org/stable/c/d3178e8a434b58678d99257c0387810a24042fb6"}],"tags":["cve.org"],"epss":0.0025,"epssPercentile":0.16461,"ingestedAt":"2026-11-05T22:38:31.751Z","slug":"CVE-2023-52928","body":"## Overview\n\nIn the Linux kernel, the following vulnerability has been resolved:\n\nbpf: Skip invalid kfunc call in backtrack_insn\n\nThe verifier skips invalid kfunc call in check_kfunc_call(), which\nwould be captured in fixup_kfunc_call() if such insn is not eliminated\nby dead code elimination. However, this can lead to the following\nwarning in backtrack_insn(), also see [1]:\n\n  ------------[ cut here ]------------\n  verifier backtracking bug\n  WARNING: CPU: 6 PID: 8646 at kernel/bpf/verifier.c:2756 backtrack_insn\n  kernel/bpf/verifier.c:2756\n\t__mark_chain_precision kernel/bpf/verifier.c:3065\n\tmark_chain_precision kernel/bpf/verifier.c:3165\n\tadjust_reg_min_max_vals kernel/bpf/verifier.c:10715\n\tcheck_alu_op kernel/bpf/verifier.c:10928\n\tdo_check kernel/bpf/verifier.c:13821 [inline]\n\tdo_check_common kernel/bpf/verifier.c:16289\n  [...]\n\nSo make backtracking conservative with this by returning ENOTSUPP.\n\n  [1] https://lore.kernel.org/bpf/CACkBjsaXNceR8ZjkLG=dT3P=4A8SBsg0Z5h5PWLryF5=ghKq=g@mail.gmail.com/\n\n## Affected\n\n- `Linux >= e6ac2450d6dee3121cd8bbf2907b78a68a8a353d < 6e2fac197de2c4c041bdd8982cffb104689113f1`\n- `Linux >= e6ac2450d6dee3121cd8bbf2907b78a68a8a353d < 74eec8266f37aff609db6a2f2b093e56a11c28c4`\n- `Linux >= e6ac2450d6dee3121cd8bbf2907b78a68a8a353d < d3178e8a434b58678d99257c0387810a24042fb6`\n- `Linux 5.13`\n\n## Remediation\n\nRefer to the linked advisories for vendor-supplied fixes and affected version ranges.","depth":"sunlit","depthScore":3,"depthScoreParts":{"impact":2.8,"likelihood":0.1,"exploitation":0,"ransomware":0},"changes":[]}