CVE-2026-55199
libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSH_MSG_EXT_INFO handl
CVSS
5.9
Medium
EPSS
0.4%
p33
KEV
—
Exploit Today
10
0-100
Published: Jun 17, 2026 · Last modified: Jul 14, 2026 · CWE-835
0.4%EPSS · 30 days0.4%
2026-06-302026-07-21
libssh2 through 1.11.1, fixed in commit 1762685, contains a pre-authentication denial of service vulnerability in the SSH_MSG_EXT_INFO handler in src/packet.c that allows a malicious SSH server to cause a client CPU exhaustion loop by sending a crafted extension count value. A malicious server can set nr_extensions to 0xFFFFFFFF during key exchange, causing the client to spin in a tight CPU loop for over 60 seconds because return values from _libssh2_get_string() are unchecked and the session timeout does not apply to CPU-bound loops.
CVECVSSEPSSKEVRExploitTitleMod.
CVE-2026-545387.5 HIG49.8%
——15xrdp is an open source RDP server. In versions 0.10.6 and prior, a n issue was discovered where the software fails to properly validate the totalLength field within the RDP protocol control header during packet reception. An unauthenticated remote attacker can exploit this vulnerability by sending a specially crafted packet that forces the xrdp process or thread into an infinite, CPU-bound loop. Because the internal pointer fails to advance and the deadlock prevention mechanism is bypassed for specific protocol data unit types, the process consumes excessive CPU resources indefinitely. This can render the xrdp service unavailable and potentially lead to system-wide resource exhaustion if multiple malicious connections are established. This issue has been fixed in version 0.10.6.1.21hCVE-2025-71397—20.7%
——6SurrealDB before 2.0.5, 2.1.x before 2.1.5, and 2.2.x before 2.2.2 allows authenticated users with OWNER or EDITOR permissions (at the root, namespace, or database level) to define custom database functions via DEFINE FUNCTION using nested FOR loops. Although a single loop's iteration count is constrained, nesting multiple loops (e.g., each with 1,000,000 iterations) is not, so an attacker can execute a function that consumes all server CPU time. Configured timeouts do not stop the execution, rendering the server unresponsive to other queries and connections until it is manually restarted.1dCVE-2026-457856.2 MED3.0%
——1OpenMcdf is a fully .NET / C# library to manipulate Compound File Binary File Format files, also known as Structured Storage. In 3.1.3 and earlier, the BST name-lookup loop in DirectoryTree.TryGetDirectoryEntry (OpenMcdf/DirectoryTree.cs:35-46) walks directory entries by repeatedly calling directories.TryGetSibling(child, siblingType, validateColor). A crafted CFB file with cyclic Left/Right sibling links among directory entries, constructed so the per-step BST-order check in TryGetSibling (DirectoryEntries.cs:84-85) is satisfied at every step, drives this while (child is not null) loop forever. There is no cycle detection in TryGetDirectoryEntry, and the bug is reachable from RootStorage.OpenStorage(name), TryOpenStorage(name), OpenStream(name), and TryOpenStream(name), causing an unrecoverable denial of service. This issue is fixed in version 3.1.4.12hCVE-2026-77715.5 MED4.5%
——1IBM Db2 11.5.0 through 11.5.9, and 12.1.0 through 12.1.4 is vulnerable to a trap when compiling a specially crafted statements containing subqueries could lead to a denial of service.13hCVE-2026-463786.2 MED1.6%
——0Dasel is a command-line tool and library for querying, modifying, and transforming data structures. From 3.0.0 until 3.10.1, the selector lexer matchRegexPattern closure in (*Tokenizer).parseCurRune in selector/lexer/tokenize.go loops while tokenizing an unterminated regex literal such as r/ because peekRuneEqual returns false after the end of input, allowing attacker-controlled selector strings to consume CPU indefinitely. This issue is fixed in version 3.10.1.4dCVE-2026-134017.5 HIG31.2%
——9XML::Bare versions through 0.53 for Perl will hang in an infinite loop when parsing malformed attributes.
The parserc_parse function never advances the attribute-parse state cursor on certain malformed attribute forms, looping forever.
Nameless attributes such as "<a ='c'>" or unbalanced quotes "<a b='''''''c'>" can trigger this condition.4d