Use-After-Free in libsoup SoupServer: TLS crash & DoS
CVE-2026-2436 Published on March 26, 2026
Libsoup: libsoup: denial of service via use-after-free in soupserver during tls handshake
A flaw was found in libsoup's SoupServer. A remote attacker could exploit a use-after-free vulnerability where the `soup_server_disconnect()` function frees connection objects prematurely, even if a TLS handshake is still pending. If the handshake completes after the connection object has been freed, a dangling pointer is accessed, leading to a server crash and a Denial of Service.
Vulnerability Analysis
CVE-2026-2436 is exploitable with network access, and does not require authorization privileges or user interaction. This vulnerability is consided to have a high level of attack complexity. The potential impact of an exploit of this vulnerability is considered to have no impact on confidentiality, with no impact on integrity, and a high impact on availability.
Timeline
Reported to Red Hat.
Made public.
Weakness Type
What is a Dangling pointer Vulnerability?
The program dereferences a pointer that contains a location for memory that was previously valid, but is no longer valid. When a program releases memory, but it maintains a pointer to that memory, then the memory might be re-allocated at a later time. If the original pointer is accessed to read or write data, then this could cause the program to read or modify data that is in use by a different function or process. Depending on how the newly-allocated memory is used, this could lead to a denial of service, information exposure, or code execution.
CVE-2026-2436 has been classified to as a Dangling pointer vulnerability or weakness.
Products Associated with CVE-2026-2436
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