// For flags

CVE-2025-12888

Constant Time Issue with Xtensa-based ESP32 and X22519

Severity Score

1.0
*CVSS v4

Exploit Likelihood

*EPSS

Affected Versions

*CPE

Public Exploits

0
*Multiple Sources

Exploited in Wild

-
*KEV

Decision

Track
*SSVC
Descriptions

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.

*Credits: Adrian Cinal
CVSS Scores
Attack Vector
Physical
Attack Complexity
High
Attack Requirements
Present
Privileges Required
Low
User Interaction
None
System
Vulnerable | Subsequent
Confidentiality
Low
Low
Integrity
None
Low
Availability
None
None
Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
None
Availability
None
Attack Vector
Network
Attack Complexity
Low
Authentication
None
Confidentiality
Partial
Integrity
None
Availability
None
* Common Vulnerability Scoring System
SSVC
  • Decision:Track
Exploitation
None
Automatable
No
Tech. Impact
Partial
* Organization's Worst-case Scenario
Timeline
  • 2025-11-07 CVE Reserved
  • 2025-11-21 CVE Published
  • 2025-12-08 CVE Updated
  • 2026-05-01 EPSS Updated
  • ---------- Exploited in Wild
  • ---------- KEV Due Date
  • ---------- First Exploit
CWE
  • CWE-203: Observable Discrepancy
CAPEC
  • CAPEC-485: Signature Spoofing by Key Recreation
Affected Vendors, Products, and Versions
Vendor Product Version Other Status
Vendor Product Version Other Status <-- --> Vendor Product Version Other Status
WolfSSL
Search vendor "WolfSSL"
 WolfSSL
Search vendor "WolfSSL" for product "WolfSSL"
 < 5.8.4
Search vendor "WolfSSL" for product "WolfSSL" and version " < 5.8.4"
en
Affected