{"id":17297,"date":"2026-09-05T02:30:58","date_gmt":"2026-09-04T18:30:58","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-80793"},"modified":"2026-09-05T02:30:58","modified_gmt":"2026-09-04T18:30:58","slug":"cve-2026-80793","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-80793","title":{"rendered":"CVE-2026-80793 &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nipv4: reject undersiz"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>ipv4: reject undersized MTUs in ip_do_fragment()<\/p>\n<p>ip_do_fragment() subtracts the IPv4 header length from the effective<br \/>\nMTU and passes the resulting payload MTU to ip_frag_next().<\/p>\n<p>If the effective MTU is smaller than hlen + 8, ip_frag_next() rounds<br \/>\nthe fragment payload length down to zero. The fragmentation state then<br \/>\nnever makes forward progress: state-&gt;left, state-&gt;ptr and state-&gt;offset<br \/>\nstay unchanged while ip_do_fragment() keeps allocating and transmitting<br \/>\nheader-only fragments until the softlockup detector fires.<\/p>\n<p>This is reproducible with a route installed using &#8220;mtu lock 20&#8221;, but it<br \/>\nis also reproducible without route MTU lock, for example by forwarding a<br \/>\npacket to a device whose MTU is 20.<\/p>\n<p>Fix it in ip_do_fragment() by rejecting mtu &lt; hlen + 8 with -EMSGSIZE,<br \/>\nmatching the existing IPv6 fragmentation check.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>ipv4: reject undersized MTUs in ip_do_fragment()<\/p>\n<p>ip_do_fragment() subtracts the IPv4 header length from the effective<br \/>\nMTU and pass<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-17297","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/17297","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=17297"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=17297"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=17297"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}