CVE-2026-94419
What it is
Without NO_SESSION_CACHE_REF, wolfSSL_get_session() does not return a session object but a ClientSession reference of the form {row, index, hash(sessionID)} into the process-global SessionCache, and ClientSessionToSession() validates it against that hash alone. Because the TLS 1.2 session ID is chosen by the server and sent in clear, AddSessionToCache() matches any other server's session on the same ID and overwrites the client-side entry with that server's master secret, cipher suite and version, while the handle continues to resolve; nothing on the write path compares the peer, the application's server ID or the WOLFSSL_CTX. Resuming through the handle then produces an abbreviated handshake in which no Certificate message is sent, so neither chain verification nor wolfSSL_check_domain_name() runs, and the attacker is accepted as the original server for the whole of that connection. Affected builds are those leaving NO_SESSION_CACHE_REF, NO_SESSION_CACHE, NO_CLIENT_CACHE and TITAN_SESSION_CACHE all undefined, which includes a plain ./configure, --enable-opensslextra and --enable-opensslall; fifteen integration options define NO_SESSION_CACHE_REF and are therefore not affected, among them --enable-all, --enable-distro, --enable-curl, --enable-nginx, --enable-haproxy, --enable-stunnel, --enable-wpas and the rest of the OPENSSL_COMPATIBLE_DEFAULTS family, and --enable-leanpsk, --enable-leantls, --enable-lowresource and --enable-tinytls13 disable the cache outright. The application must use the legacy reference flow, wolfSSL_get_session() or SSL_get_session() followed by wolfSSL_set_session(); wolfSSL_get1_session() returns the session object itself and is not affected, nor are wolfSSL_SetServerID() lookups. Only TLS 1.2 and below and DTLS 1.2 and below are reachable, since TLS 1.3 and ticket resumption with an empty ServerHello session ID both use a client-chosen cache key. The poisoned entry lives in the process-global cache, so it crosses WOLFSSL_CTX boundaries and persists until the entry is evicted or the session times out, 500 seconds by default. Releases v5.3.0 through v5.9.2 are affected; the fix adds a per-write generation counter to the cache and raises WOLFSSL_CACHE_VERSION from 2 to 3, so a cache persisted by an older build is rejected by a fixed one.
At a glance
- Exploitability
- Can be exploited from the same network segment without logging in. Limited direct impact.
- Exploit odds
- 0.1% chance of exploitation in the next 30 days (EPSS).
- Fix
- A patch, advisory or fixed version is referenced. Upgrade or apply it.
Timeline
- PublishedDisclosed publicly on CVE.org and NVD
- Last updatedMost recent change to the record
Why it ranks here
- Exploited in the wild: no, CISA does not list it.
- Exploit odds: 0.1% in the next 30 days (EPSS).
- Severity: 2.3 LOW (CVSS).
- Fix: a patch or advisory is linked.
Details
- Published
- Last modified
- Exploit probability
- 0.1% · EPSS, next 30 days
- Weakness
- CWE-287 · Improper authentication
- Record status
- Analyzed
Affected
- Wolfssl ≤ 5.9.2
Attack profile CVSS 4.0 · 2.3
- Attack vector
- Adjacent network
- Complexity
- High
- Attack requirements
- Present
- Privileges needed
- None
- User interaction
- None
- Confidentiality
- Low
- Integrity
- Low
- Availability
- None
Raw vector
CVSS:4.0/AV:A/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
Is it in your code?
Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.
Read https://cve-list.com/agent/cve/CVE-2026-94419.md and follow it. Check whether this project is affected by CVE-2026-94419. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.
