What’s Vulnerable › Vulnerabilities

CVE-2025-12888: Constant Time Issue with Xtensa-based ESP32 and X22519

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 0.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2025-11-21 · updated 2026-10-19
• Weakness: CWE-203

Description

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.

Affected products

• wolfSSL: 5.8.2

References

• https://https://github.com/wolfSSL/wolfssl/pull/9275

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