Fix in 1 min {openssl:error:0a00018e:ssl routines::ca md too weak

In today’s digital age, security is paramount. When it comes to securing online communications, SSL/TLS (Secure Sockets Layer/Transport Layer Security) protocols play a crucial role. However, encountering an error like “openssl: error:0A00018E:SSL routines::ca md too weak” can be a cause for concern.

In this article, we will delve into the intricacies of this error and explore effective ways to resolve it, ensuring your online activities remain safe and secure.

Understanding the Error

openssl:error:0a00018e:ssl routines::ca md too weak

Before we delve into the solutions, let’s decipher the cryptic error message: “openssl: error:0A00018E:SSL routines::ca md too weak.” This error is essentially a warning from the OpenSSL library, indicating that a Certificate Authority (CA) certificate with a weak hash algorithm has been detected. But what does this mean, and why should you care?

Weak hash algorithms in SSL/TLS certificates can open the door to security vulnerabilities. These certificates are the foundation of secure communication on the internet, and any compromise in their integrity can lead to data breaches and other cyber threats. Now, let’s explore the implications of such weak CA certificates.

Now that we understand the gravity of the situation, let’s explore how to fix the “openssl: error:0A00018E:SSL routines::ca md too weak” error.

Methods to Fix the Error

There are three primary methods to resolve this error, each with its own considerations. Choose the one that best suits your situation:

Updating the CA Certificate

  1. Contact the CA: Contact the Certificate Authority (CA) that issued the weak certificate. Request a new certificate that uses a stronger hash algorithm.
  2. Import the New Certificate: Import it into your trust store once you receive the updated certificate. This ensures that your system recognizes it as a trusted certificate.
  3. Restart Your VPN Client: To apply the changes, restart your VPN client. This step is crucial to ensure that the new certificate is actively used for secure connections.

Using a Different SSL/TLS Library

If updating the CA certificate isn’t feasible, consider switching to a different SSL/TLS library. Two popular alternatives are GnuTLS and LibreSSL. Here’s how to go about it:

  1. Install the Library: Install your chosen library, GnuTLS or LibreSSL, on your system.
  2. Configure Your VPN Client: Modify your VPN client settings to use the newly installed library instead of OpenSSL. Consult your client’s documentation for guidance on this configuration.

Disabling Weak Hash Algorithm Checks (As a Temporary Solution)

While not recommended for long-term use due to security implications, you can temporarily disable the check for weak hash algorithms in OpenSSL. Here’s how:

  1. Open the OpenSSL Configuration File: Locate and open the OpenSSL configuration file on your system.
  2. Modify Default Settings: In the configuration file, find the line that reads default-md = sha1. Change the value of sha1 to NULL.
  3. Save and Restart: Save the configuration file and restart your VPN client. This step will implement the change.

Types of OpenSSL errors

Openssl ErrorCause
openssl: error:0A00018E:SSL routines::ca md too weakThe OpenSSL library has detected a Certificate Authority (CA) certificate with a weak hash algorithm.
java.lang.NullPointerExceptionA null pointer has been dereferenced. This can happen when a variable is not initialized or when a reference to an object is lost.
System.OutOfMemoryErrorThe Java Virtual Machine (JVM) has run out of memory. This can happen when the JVM is trying to allocate too much memory or when the heap is too fragmented.
ArithmeticExceptionAn arithmetic operation has resulted in an invalid value. This can happen when dividing by zero or taking a negative number’s square root.
ArrayIndexOutOfBoundsExceptionAn array index is out of bounds. This can happen when an index is less than zero or greater than the length of the array.
ClassCastExceptionAn attempt has been made to cast an object to a class that it does not belong to. This can happen when an object is of the wrong type or when the object has been corrupted.
IOExceptionAn I/O error has occurred. This can happen when reading or writing to a file or when connecting to a network resource.
ParseExceptionA parsing error has occurred. This can happen when parsing a string or when reading from a file.
SQLExceptionA SQL error has occurred. This can happen when executing a SQL statement or when connecting to a database.
RuntimeExceptionAn unexpected runtime error has occurred. This can happen when a Java library throws an error or when an application code has an error.

Impact of Weak CA Certificates

Weak CA certificates can have far-reaching consequences. Here are some of the potential risks associated with them:

  1. Data Interception: Attackers can exploit weak certificates to intercept sensitive data transmitted between you and a server, leading to data leaks or unauthorized access.
  2. Man-in-the-Middle Attacks: Weak certificates make it easier for cybercriminals to execute man-in-the-middle attacks, where they secretly intercept and possibly alter your communication.
  3. Identity Spoofing: Attackers can impersonate legitimate websites or services, leading users to unknowingly interact with malicious entities.
  4. Loss of Trust: Weak security erodes user trust in online platforms, potentially causing reputational damage.


Securing your online communication is of utmost importance in today’s digital landscape. The “openssl: error:0A00018E:SSL routines::ca md too weak” error may appear daunting, but with the right steps, it can be addressed effectively. Whether you choose to update the CA certificate, switch to a different SSL/TLS library, or temporarily disable weak hash algorithm checks, remember that your online security should never be compromised.


Q1: What is a Certificate Authority (CA)?

A1: A Certificate Authority (CA) is a trusted entity responsible for issuing digital certificates that verify the identity of websites and online services.

Q2: Why are weak hash algorithms a security concern?

A2: Weak hash algorithms can be exploited by attackers to compromise the integrity of SSL/TLS certificates, leading to data breaches and cyberattacks.

Q3: Is it safe to disable weak hash algorithm checks in OpenSSL?

A3: Disabling these checks should only be a temporary solution, as it reduces security. It's crucial to seek a more robust, long-term fix.

Q4: How often should I update my CA certificate?

A4: CA certificates should be updated as per the CA's recommendations or when security vulnerabilities are identified.

Q5: Can I use a different SSL/TLS library with any VPN client?

A5: The compatibility of different libraries with VPN clients may vary. Consult your client's documentation for guidance on library switching.