CVE-2026-15442: Heap use-after-free on read during bidirectional (D)TLS shutdown

Vulnerability summary

CVE-2026-15442 is a medium (CVSS 5.3) Use After Free vulnerability in wolfssl. EPSS estimates a 0.21% chance of exploitation in the next 30 days, higher than 10.8% of scored vulnerabilities.

Timeline

1. 27-09-2026
   PublishedVulnerability first disclosed.
2. 30-09-2026
   Last modifiedVulnerability information updated.

Description

In all builds that make use of (D)TLS, including default builds, there is a series of conditional states during the TLS shutdown which could lead to a heap-use-after free. If an application ended up getting a partial wolfSSL_read() which is sometimes caused by a small user buffer passed in, then called wolfSSL_shutdown for a bidirectional close and attempted to wolfSSL_read() again while the peer continues trying to send data during the shutdown it would lead to a state where a potential heap-use-after free happened.

• CWE-416Use After FreeThe product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory "belongs" to the code that operates on the new pointer.