Linux app fails to communicate on Fedora 41

[Withalion]

After moving to Qt 6.8.3 the linux app fails on Fedora 41. CMake & Build passes without issues, but app can't find OpenSSL during runtime and all communications are failing.

I get mixture of these errors:

qt.network.ssl: The backend "cert-only" does not support QSslKey
qt.network.ssl: Active TLS backend does not support key creation
qt.network.ssl: QSslSocket::connectToHostEncrypted: TLS initialization failed

When trying to get some more debug info from Qt I got this:

  qDebug() << "Version: " << QSslSocket::sslLibraryVersionString();
  qDebug() << "Version build: " << QSslSocket::sslLibraryBuildVersionString();
  qDebug() << "Supports: " << QSslSocket::supportsSsl();
  qDebug() << "Backends: " << QSslSocket::availableBackends();

Version:  ""
Version build:  ""
Supports:  false
Backends:  QList("cert-only")

Quick-fix:
Change lookup locations for openssl in cmake/FindOpenSSL.cmake to system location.

find_path(
  OpenSSL_INCLUDE_DIR
  openssl/ssl.h
  "/usr/include"
  NO_DEFAULT_PATH
)

find_library(
  OpenSSL_CRYPTO_LIBRARY
  NAMES crypto libcrypto
  PATHS "/usr/lib"
  NO_DEFAULT_PATH
)

find_library(
  OpenSSL_LIBRARY
  NAMES ssl libssl
  PATHS "/usr/lib"
  NO_DEFAULT_PATH
)

[Withalion]

Looks like it was a temporary upstream issue, fixed by updating system packages.

[Withalion]

The issue is Fedora specific, however updating now probably doesn't solve the issue as it is still relevant in Fedora 41/42. In Fedora 43 the openssl package should be updated to 3.5.0, which corresponds to version we use and that might solve it.
Another workaround to use is moving/renaming etc/ssl/openssl.cnf, after which Qt is able to find openssl library again. (Usable with VCPKG)

Relevant vcpkg issues:
microsoft/vcpkg#46047
microsoft/vcpkg#46031