CVE-2026-77131 in SYSSY
Summary
by MITRE • 08/25/2026
When OpenSSL is unavailable on the server, the extension transmits TYPO3 system information in cleartext instead of encrypting it. Exploitation requires the attacker to already be in control of the SYSSY project's API key.
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Analysis
by VulDB Data Team • 08/25/2026
The vulnerability described involves a critical failure in cryptographic implementation within the TYPO3 ecosystem, specifically affecting extensions that rely on OpenSSL for secure communication with external APIs such as those associated with the SYSSY project. In standard security architectures, sensitive system information transmitted between client and server components must be encrypted to prevent interception by unauthorized parties. However, when the OpenSSL extension is unavailable or disabled on the target server, the application fails to enforce encryption protocols. Instead of falling back to a secure state or rejecting the connection, it defaults to transmitting data in cleartext. This behavior represents a significant deviation from expected security postulates, as it exposes internal system details that should remain confidential under normal operational conditions.
From a technical perspective, this flaw stems from inadequate error handling and missing fallback mechanisms within the extension code. Rather than validating the availability of cryptographic libraries before initiating sensitive data transmission, the software proceeds with plaintext communication if OpenSSL is not detected. This lack of defensive programming allows an attacker who has obtained valid API credentials to intercept unencrypted network traffic containing valuable system information. The presence of such a flaw indicates that the application does not strictly enforce encryption requirements as part of its authentication or authorization workflow, thereby creating a window for data exfiltration even when access controls are technically in place via API keys.
The operational impact of this vulnerability is primarily centered around confidentiality breaches rather than integrity or availability issues. An attacker possessing control over the SYSSY project's API key can leverage network sniffing tools to capture and analyze the cleartext transmissions. This information may include server configurations, installed extensions, database structures, or other metadata that aids in further reconnaissance efforts. While the requirement for an existing API key limits the attack surface to authenticated users or compromised accounts, it does not eliminate risk entirely since internal credentials can be stolen through phishing, insider threats, or previous breaches of authentication systems. The exposure of system information facilitates more targeted attacks against specific TYPO3 instances by revealing potential weaknesses in their current setup.
This vulnerability aligns with CWE-209, which describes the generation of an error message that includes sensitive information about the environment, and CWE-319 regarding cleartext transmission of sensitive information. Additionally, it relates to ATT&CK technique T1504, specifically the use of compromised credentials for lateral movement or data collection phases where encrypted channels are bypassed due to implementation flaws. To mitigate this issue, developers must implement strict validation checks that ensure OpenSSL is available and functional before allowing any transmission of sensitive data. If cryptographic libraries are missing, the system should either refuse operation entirely or route traffic through a secure proxy rather than defaulting to plaintext. Administrators should also monitor for unexpected cleartext connections involving API endpoints and enforce TLS requirements at both application and network levels to prevent such fallback behaviors from being exploited in production environments.