CVE-2026-94419: wolfSSL session cache poisoning in TLS 1.2 resumption

CVE-2026-94419 · Severity: info · Published 2026-09-27

wolfSSL's session cache can be poisoned if NO_SESSION_CACHE_REF is not explicitly disabled at compile time, allowing an attacker to inject a malicious server's session credentials into a client's cache. When a legitimate connection is resumed through the poisoned cache entry, the client skips certificate verification and accepts the attacker as the original server, potentially enabling man-in-the-middle attacks or account takeover. This affects default and several common builds; most enterprise-focused builds are protected.

Technologies: Wolfssl. Vendors: Wolfssl.

Quick answers

Is CVE-2026-94419 exploited in the wild?
No. Junglewise Threat Intelligence has no report of CVE-2026-94419 being exploited in the wild.
How severe is CVE-2026-94419?
Informational severity, published 27 September 2026.
Which products and versions are affected?
Wolfssl v5.3.0 through v5.9.2.
Is there a fix for CVE-2026-94419?
No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
How is CVE-2026-94419 attacked?
It is attacked over the network or from the adjacent network, in a software library.
Am I affected by CVE-2026-94419?
Check whether you run Wolfssl at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

Technical details

The vulnerability exists in wolfSSL's session caching mechanism for TLS 1.2 and DTLS 1.2 when using the legacy reference-based session flow (wolfSSL_get_session/SSL_get_session followed by wolfSSL_set_session). An attacker can inject a crafted session into the process-global SessionCache by reusing a server-chosen session ID; the cache lacks peer identity validation during writes, allowing overwrite of legitimate client entries. Abbreviated handshakes using the poisoned entry skip Certificate message transmission, bypassing domain name verification. The fix adds per-write generation counters and increments the cache version, invalidating caches from older builds.

Affected products

  • wolfSSL wolfSSL v5.3.0 through v5.9.2

Timeline

  • 2026-09-27: disclosed

This page as Markdown. Free to reuse under CC BY 4.0 with a link back.