Fix bad deref when ciphersuite value is larger than largest known id

Reported by @neverhub in GH #758 found by libFuzzer

1 files changed, 1 insertions, 1 deletions

diff --git a/src/lib/tls/tls_ciphersuite.cpp b/src/lib/tls/tls_ciphersuite.cpp
index a15f936be..08ef8e812 100644
--- a/src/lib/tls/tls_ciphersuite.cpp
+++ b/src/lib/tls/tls_ciphersuite.cpp
@@ -45,7 +45,7 @@ Ciphersuite Ciphersuite::by_id(u16bit suite)
    const std::vector<Ciphersuite>& all_suites = all_known_ciphersuites();
    auto s = std::lower_bound(all_suites.begin(), all_suites.end(), suite);
 
-   if(s->ciphersuite_code() == suite)
+   if(s != all_suites.end() && s->ciphersuite_code() == suite)
       {
       return *s;
       }