# CVE-2025-12888: Vulnerability in X25519 constant-time cryptographic implementations due to timing side channels introduced by compiler…

Source: https://junglewise.ai/threats/cve-2025-12888-vulnerability-in-x25519-constant-time-cryptographic  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2025-11-21  
License: CC BY 4.0 with a link back

CVE-2025-12888 · Severity: high · CVSS 7.5 · Published 2025-11-21

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.

Technologies: [Wolfssl](https://junglewise.ai/threats/technologies/wolfssl). Vendors: [Wolfssl](https://junglewise.ai/threats/vendors/wolfssl).

## Quick answers

**Is CVE-2025-12888 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2025-12888 being exploited in the wild.

**How severe is CVE-2025-12888?** High severity, with a CVSS score of 7.5, published 21 November 2025.

**Which products and versions are affected?** Wolfssl. The advisory does not name versions.

**Is there a fix for CVE-2025-12888?** No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.

**Am I affected by CVE-2025-12888?** Check whether you run Wolfssl. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.

## Affected products

- Wolfssl

## Related threats

- [wolfSSL certificate validation bypass in ConfirmNameConstraints()](https://junglewise.ai/threats/cve-2026-95208-an-issue-in-the-confirmnameconstraints-function-wolfcrypt-src-asn)
- [wolfSSL revocation check bypass with OCSP and CRL](https://junglewise.ai/threats/cve-2026-94417-when-an-application-enables-both-ocsp-and-crl-revocation-checking)
- [wolfSSL TLS 1.2 ChangeCipherSpec message ordering bypass](https://junglewise.ai/threats/cve-2026-93304-a-d-tls-1-2-client-can-accept-a-changecipherspec-message-before)
- [wolfSSL MatchTrustedPeer public key validation bypass](https://junglewise.ai/threats/cve-2026-93302-matchtrustedpeer-ignores-the-public-key-used-leading-to-forged-ca)
- [wolfSSL TLS authentication bypass in Raw Public Key handling](https://junglewise.ai/threats/cve-2026-89136-when-using-rpk-raw-public-key-the-client-side-of-a-tls-1-2-1-3)