CVE-2026-66034
libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing bounds check vulnerability that allows a malicious SSH server to trigger an arbitrary-length heap out-of-bounds read and a free of an uninitialized pointer via the publickey subsystem. In libssh2_publickey_list_fetch(), the version 1 response parser reads a server-controlled comment_len value and advances the parse pointer without verifying sufficient bytes remain in the buffer, causing the out-of-bounds read to leak heap pointers from adjacent allocations defeating ASLR, followed by heap allocator state corruption when the error cleanup path frees an uninitialized pointer from a non-zeroed realloc() region.
Matched ports (2)
| Port | Package | Version | Status | Maintainer |
|---|---|---|---|---|
| security/libssh2 | libssh2 | 1.11.1_1,3 | unaddressed | sbz@FreeBSD.org |
| security/linux-c7-libssh2 | linux-c7-libssh2 | 1.8.0_2 | unaddressed | emulation@FreeBSD.org |
Template for a VuXML entry
Range taken from the CVE record, check it before committing. make newentry in security/vuxml creates the vid.
<vuln vid="FIXME (make newentry)">
<topic>FIXME -- FIXME</topic>
<affects>
<package>
<name>libssh2</name>
<range><lt>FIXME</lt></range>
</package>
<package>
<name>linux-c7-libssh2</name>
<range><lt>FIXME</lt></range>
</package>
</affects>
<description>
<body xmlns="http://www.w3.org/1999/xhtml">
<p>libssh2 through 1.11.1, fixed in commit a13bb6c, contains a missing
bounds check vulnerability that allows a malicious SSH server to
trigger an arbitrary-length heap out-of-bounds read and a free of an
uninitialized pointer via the publickey subsystem. In
libssh2_publickey_list_fetch(), the version 1 response parser reads a
server-controlled comment_len value and advances the parse pointer
without verifying sufficient bytes remain in the buffer, causing the
out-of-bounds read to leak heap pointers from adjacent allocations
defeating ASLR, followed by heap allocator state corruption when the
error cleanup path frees an uninitialized pointer from a non-zeroed
realloc() region.</p>
</body>
</description>
<references>
<cvename>CVE-2026-66034</cvename>
<url>https://nvd.nist.gov/vuln/detail/CVE-2026-66034</url>
</references>
<dates>
<discovery>2026-07-24</discovery>
<entry>2026-10-26</entry>
</dates>
</vuln>