CVE-2026-55199: Libssh2 Security Vulnerability (CVSS 8.2)

libssh2 through 1.11.1 reads an attacker-controlled 32-bit attribute count from a publickey-subsystem response and uses it in the allocation num_attrs * sizeof(libssh2_publickey_attribute) without bounds checking, so on 32-bit platforms the multiplication overflows to an undersized buffer. A malicious SSH server can then drive the attribute-parsing loop to write past the allocation, causing a heap buffer overflow in a connecting libssh2 client.

libssh2 through 1.11.1, fixed in commit 7acf3df contains an out-of-bounds write vulnerability in ssh2_transport_read() that fails to enforce upper bounds on packet_length field. Remote attackers can send crafted SSH packets with excessively large packet_length values to corrupt heap memory and achieve remote code execution.

Marked is a markdown parser and compiler. From 18.0.0 to 18.0.1, a critical Denial of Service (DoS) vulnerability exists in marked. By providing a specific 3-byte input sequence a tab, a vertical tab, and a newline (\x09\x0b\n)—an unauthenticated attacker can trigger an infinite recursion loop during parsing. This leads to unbounded memory allocation, causing the host Node.js application to crash via Memory Exhaustion (OOM). This vulnerability is fixed in 18.0.2.

Immutable.js provides many Persistent Immutable data structures. Prior to 4.3.9 and 5.1.8, List#set, List#setSize, List#setIn, List#updateIn, and the functional set, setIn, and updateIn mishandle an index or size in the range 2 ** 30 to 2 ** 31 in setListBounds in src/List.js, causing an empty List to enter an uncatchable infinite loop, a populated List to allocate without bound until process abort, or setSize to silently wrap large values. This issue is fixed in versions 4.3.9 and 5.1.8.

Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in mtrudel bandit allows unauthenticated remote denial of service via worker process exhaustion. 'Elixir.Bandit.HTTP1.Socket':do_read_chunked_data!/5 in lib/bandit/http1/socket.ex terminates only when the last-chunk line 0\r\n is followed immediately by the empty trailer line \r\n. RFC 9112 §7.1.2 permits zero or more trailer fields between them. When trailers are present, none of the match clauses fit: the catch-all arm computes a negative to_read, calls read_available!/2, receives <<>> on timeout, and tail-recurses with unchanged state. The worker process is pinned for the lifetime of the TCP connection. A handful of concurrent connections sending RFC-conformant chunked requests with trailer fields is sufficient to exhaust the Bandit worker pool and render the server unresponsive to all further traffic. No authentication, special headers, or large payload is required. Proxies such as NGINX and HAProxy legitimately forward trailer-bearing requests, so servers behind such proxies may be affected without any malicious client involvement. This issue affects bandit: from 1.6.1 before 1.11.1.

Loop with Unreachable Exit Condition ('Infinite Loop') vulnerability in benoitc hackney allows Excessive Allocation. The Alt-Svc response header parser in src/hackney_altsvc.erl does not guarantee forward progress. When parse_token/2 receives a non-token, non-whitespace, non-comma byte (e.g. !, @, =, ;), it returns the input unchanged. skip_comma/1 also returns the buffer unchanged when the first byte is not a comma. parse_entries/2 then recurses with identical data, creating a tight infinite tail-recursive loop that pins a scheduler at 100% CPU. The calling process never returns. The entry point parse_and_cache/3 is called synchronously in the connection process on every HTTP response. A single-byte Alt-Svc: ! response header is sufficient to trigger the hang; the header is fully controlled by any HTTP origin the client connects to. This issue affects hackney: from 2.0.0-beta.1 before 4.0.1.