wolfSSL 5.8.2 X25519 information exposure

Summaryinfo

A vulnerability classified as problematic was found in wolfSSL 5.8.2. The affected element is an unknown function of the component X25519. Such manipulation leads to information exposure. This vulnerability is traded as CVE-2025-12888. The attack can be executed directly on the physical device. There is no exploit available. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability was found in wolfSSL 5.8.2 and classified as problematic. Affected by this issue is an unknown function of the component X25519. The manipulation with an unknown input leads to a information exposure vulnerability. Using CWE to declare the problem leads to CWE-203. The product behaves differently or sends different responses under different circumstances in a way that is observable to an unauthorized actor, which exposes security-relevant information about the state of the product, such as whether a particular operation was successful or not. Impacted is confidentiality. CVE summarizes:

Vulnerability in X25519 constant-time cryptographic implementations due to timing side channels introduced by compiler optimizations and CPU architecture limitations, specifically with the Xtensa-based ESP32 chips. If targeting Xtensa it is recommended to use the low memory implementations of X25519, which is now turned on as the default for Xtensa.

The weakness was shared by Adrian Cinal. The advisory is shared for download at github.com. This vulnerability is handled as CVE-2025-12888 since 11/07/2025. The exploitation is known to be difficult. The attack needs to be approached locally. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1592.

The vulnerability scanner Nessus provides a plugin with the ID 276566 (Linux Distros Unpatched Vulnerability : CVE-2025-12888), which helps to determine the existence of the flaw in a target environment.

Applying a patch is able to eliminate this problem. The bugfix is ready for download at github.com.

The vulnerability is also documented in the vulnerability database at Tenable (276566). Once again VulDB remains the best source for vulnerability data.

Productinfo

Name

• wolfSSL

Version

• 5.8.2

License

• open-source

Website

• Product: https://github.com/wolfSSL/wolfssl/

CPE 2.3info

• 🔒

CPE 2.2info

• 🔒

CVSSv4info

CVSSv3info

CVSSv2info

Exploitinginfo

Threat Intelligenceinfo

Countermeasuresinfo

Timelineinfo

Sourcesinfo

Entryinfo

Once again VulDB remains the best source for vulnerability data.

Discussion