{"id":14969,"date":"2026-09-04T19:02:20","date_gmt":"2026-09-04T11:02:20","guid":{"rendered":"https:\/\/www.54iter.cn\/?vuln=cve-2026-63939"},"modified":"2026-09-04T19:02:20","modified_gmt":"2026-09-04T11:02:20","slug":"cve-2026-63939","status":"publish","type":"vuln","link":"https:\/\/www.54iter.cn\/?vuln=cve-2026-63939","title":{"rendered":"CVE-2026-63939 [CRITICAL] &#8211; In the Linux kernel, the following vulnerability has been resolved:\n\nKVM: SEV: Compute the"},"content":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>KVM: SEV: Compute the correct max length of the in-GHCB scratch area<\/p>\n<p>When setting the length of the GHCB scratch area, and the area is in the<br \/>\nGHCB shared buffer, set the effective length of the scratch area to the max<br \/>\npossible size given the start of the guest-provided pointer, and the end of<br \/>\nthe shared buffer.<\/p>\n<p>The code was &#8220;fine&#8221; when first introduced, as KVM doesn&#8217;t consult the<br \/>\nlength of the buffer when emulating MMIO, because the passed in @len always<br \/>\nspecifies the *max* size required.  But for PSC requests, the incoming @len<br \/>\nis just the minimum length (to process the header), and KVM needs to know<br \/>\nthe full size of the scratch area to avoid buffer overflows (spoiler alert).<\/p>\n<p>Opportunistically rename @len =&gt; @min_len to better reflect its role.<\/p>\n","protected":false},"excerpt":{"rendered":"<p>In the Linux kernel, the following vulnerability has been resolved:<\/p>\n<p>KVM: SEV: Compute the correct max length of the in-GHCB scratch area<\/p>\n<p>When setting the length of the GHCB scratch area, and the are<\/p>\n","protected":false},"template":"","meta":[],"categories":[],"tags":[],"class_list":["post-14969","vuln","type-vuln","status-publish","hentry"],"_links":{"self":[{"href":"https:\/\/www.54iter.cn\/index.php?rest_route=\/wp\/v2\/vuln\/14969","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=14969"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Fcategories&post=14969"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/www.54iter.cn\/index.php?rest_route=%2Fwp%2Fv2%2Ftags&post=14969"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}