{"id":29204,"date":"2026-09-25T20:32:08","date_gmt":"2026-09-25T12:32:08","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-98049"},"modified":"2026-09-25T20:32:08","modified_gmt":"2026-09-25T12:32:08","slug":"cve-2026-98049","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-98049","title":{"rendered":"CVE-2026-98049 &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nbpf: zero extend the"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>bpf: zero extend the result of an arena 32-bit cmpxchg<\/p>\n<p>bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from<br \/>\nBPF_STX | BPF_ATOMIC to BPF_STX | BPF_PROBE_ATOMIC, and it runs before<br \/>\nbpf_opt_subreg_zext_lo32_rnd_hi32().<\/p>\n<p>That pass emits an explicit zero extension for a 32-bit cmpxchg even<br \/>\nwhen bpf_jit_needs_zext() is false. This is done because on some<br \/>\narchitectures 32-bit cmpxchg requires explicit zero extension for the<br \/>\ndst register. E.g. on x86-64 &#8216;lock cmpxchg&#8217; does not change the %eax<br \/>\nif comparison is successful, while BPF semantics declare that each<br \/>\noperation on a 32-bit register zero extends it&#8217;s upper half.<\/p>\n<p>is_cmpxchg_insn() matches BPF_MODE == BPF_ATOMIC only, so an arena<br \/>\ncmpxchg misses said zero extension adjustment. This patch adjusts<br \/>\nis_cmpxchg_insn() to match BPF_PROBE_ATOMIC alongside BPF_ATOMIC.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>bpf: zero extend the result of an arena 32-bit cmpxchg<\/p>\n<p>bpf_convert_ctx_accesses() rewrites an atomic on an arena pointer from<br \/>\nBPF_<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-29204","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/29204","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln"}],"about":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/types\/vuln"}],"wp:attachment":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fmedia&parent=29204"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=29204"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=29204"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}