{"id":82515,"date":"2026-07-24T20:47:35","date_gmt":"2026-07-24T17:17:35","guid":{"rendered":"https:\/\/afaghhosting.net\/blog\/cve-2026-66035-libssh2-heap-buffer-overflow-via-etm-cipher-negotiation\/"},"modified":"2026-07-24T20:47:35","modified_gmt":"2026-07-24T17:17:35","slug":"cve-2026-66035-libssh2-heap-buffer-overflow-via-etm-cipher-negotiation","status":"publish","type":"post","link":"https:\/\/afaghhosting.net\/blog\/cve-2026-66035-libssh2-heap-buffer-overflow-via-etm-cipher-negotiation\/","title":{"rendered":"CVE-2026-66035 &#8211; libssh2 Heap Buffer Overflow via ETM Cipher Negotiation"},"content":{"rendered":"<p>CVE ID :CVE-2026-66035<\/p>\n<p>  Published : July 24, 2026, 5:17 p.m. | 32\u00a0minutes ago<\/p>\n<p>  Description :libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet_length smaller than the cipher&#8217;s block size during Encrypt-then-MAC cipher negotiation. In the fullpacket() function in src\/transport.c, the ETM path allocates a buffer of packet_length bytes but copies blocksize minus one bytes via memcpy, causing an overflow that on 32-bit glibc writes attacker-controlled bytes into an adjacent chunk&#8217;s SIZE field, enabling tcache bin confusion, overlapping live objects, and function pointer overwrite during the session handshake before authentication.<\/p>\n<p>  Severity: 7.7 | HIGH<\/p>\n<p>  Visit the link for more details, such as CVSS details, affected products, timeline, and more&#8230;\u00a0<\/p>\n","protected":false},"excerpt":{"rendered":"<p>CVE ID :CVE-2026-66035 Published : July 24, 2026, 5:17 p.m. | 32\u00a0minutes ago Description :libssh2 through 1.11.1, fixed in commit 42e33d8, contains a pre-authentication heap buffer overflow vulnerability that allows a malicious SSH server to corrupt heap metadata in any connecting client by sending a packet with a packet_length smaller than the cipher&#8217;s block size &hellip;<\/p>\n","protected":false},"author":1,"featured_media":0,"comment_status":"closed","ping_status":"closed","sticky":false,"template":"","format":"standard","meta":{"footnotes":""},"categories":[26],"tags":[],"class_list":["post-82515","post","type-post","status-publish","format-standard","hentry","category-vulnerability"],"_links":{"self":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/82515","targetHints":{"allow":["GET"]}}],"collection":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts"}],"about":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/types\/post"}],"author":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/users\/1"}],"replies":[{"embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/comments?post=82515"}],"version-history":[{"count":0,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/posts\/82515\/revisions"}],"wp:attachment":[{"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/media?parent=82515"}],"wp:term":[{"taxonomy":"category","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/categories?post=82515"},{"taxonomy":"post_tag","embeddable":true,"href":"https:\/\/afaghhosting.net\/blog\/wp-json\/wp\/v2\/tags?post=82515"}],"curies":[{"name":"wp","href":"https:\/\/api.w.org\/{rel}","templated":true}]}}