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Published: 31 August 2022

An issue was discovered in wolfSSL before 5.5.0 (when --enable-session-ticket is used); however, only version 5.3.0 is exploitable. Man-in-the-middle attackers or a malicious server can crash TLS 1.2 clients during a handshake. If an attacker injects a large ticket (more than 256 bytes) into a NewSessionTicket message in a TLS 1.2 handshake, and the client has a non-empty session cache, the session cache frees a pointer that points to unallocated memory, causing the client to crash with a "free(): invalid pointer" message. NOTE: It is likely that this is also exploitable during TLS 1.3 handshakes between a client and a malicious server. With TLS 1.3, it is not possible to exploit this as a man-in-the-middle.



Cvss 3 Severity Score


Score breakdown


Package Release Status
Launchpad, Ubuntu, Debian
bionic Needs triage

focal Needs triage

jammy Needs triage

kinetic Ignored
(end of life, was needs-triage)
lunar Ignored
(end of life, was needs-triage)
mantic Needs triage

trusty Does not exist

upstream Needs triage

xenial Needs triage

Severity score breakdown

Parameter Value
Base score 5.9
Attack vector Network
Attack complexity High
Privileges required None
User interaction None
Scope Unchanged
Confidentiality None
Integrity impact None
Availability impact High
Vector CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H