diff --git a/pkgs/development/libraries/libressl/default.nix b/pkgs/development/libraries/libressl/default.nix
index c091a1b698d2..0d01eeb81f1a 100644
--- a/pkgs/development/libraries/libressl/default.nix
+++ b/pkgs/development/libraries/libressl/default.nix
@@ -49,8 +49,11 @@ let
 
     # Since 2.9.x the default location can't be configured from the build using
     # DEFAULT_CA_FILE anymore, instead we have to patch the default value.
-    postPatch = lib.optionalString (lib.versionAtLeast version "2.9.2") ''
-      substituteInPlace ./tls/tls_config.c --replace '"/etc/ssl/cert.pem"' '"${cacert}/etc/ssl/certs/ca-bundle.crt"'
+    postPatch = ''
+      patchShebangs tests/
+      ${lib.optionalString (lib.versionAtLeast version "2.9.2") ''
+        substituteInPlace ./tls/tls_config.c --replace '"/etc/ssl/cert.pem"' '"${cacert}/etc/ssl/certs/ca-bundle.crt"'
+      ''}
     '';
 
     doCheck = true;