{"id":25459,"date":"2026-09-18T04:31:24","date_gmt":"2026-09-17T20:31:24","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-90050"},"modified":"2026-09-18T04:31:24","modified_gmt":"2026-09-17T20:31:24","slug":"cve-2026-90050","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-90050","title":{"rendered":"CVE-2026-90050 &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nnet\/sched: fq: clamp"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>net\/sched: fq: clamp quantum and initial_quantum in change path<\/p>\n<p>The fq change path accepts TCA_FQ_QUANTUM in [1, INT_MAX] and<br \/>\nTCA_FQ_INITIAL_QUANTUM up to INT_MAX, while fq_init() already clamps to<br \/>\n[1, 1&lt;&lt;20]. A user can override the init clamp via tc qdisc change,<br \/>\nrestoring the small-quantum deficit spin that the init clamp prevents.<\/p>\n<p>Narrow iq_range.max to 1&lt;&lt;20 so TCA_FQ_INITIAL_QUANTUM is rejected at<br \/>\nparse time. Clamp TCA_FQ_QUANTUM to [256, 1&lt;&lt;20] in fq_change() and<br \/>\nfq_init() quantum to [256, 1&lt;&lt;20] for tiny-MTU devices.<\/p>\n<p>Conditions to recreate the bug:<br \/>\n  CONFIG_NET_SCH_FQ=y. Requires CAP_NET_ADMIN (namespace-local via<br \/>\n  unshare -Urn suffices).<\/p>\n<p>  tc qdisc add dev dummy0 root fq<br \/>\n  tc qdisc change dev dummy0 root fq quantum 1 stab data 32768 size_log 15 cell_log 0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>net\/sched: fq: clamp quantum and initial_quantum in change path<\/p>\n<p>The fq change path accepts TCA_FQ_QUANTUM in [1, INT_MAX] and<br \/>\nTCA_<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-25459","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/25459","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=25459"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=25459"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=25459"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}