High severity · published Nov 21, 2025
CVE-2025-12888
Constant Time Issue with Xtensa-based ESP32 and X22519
7.5
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
None
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 23% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
WO
wolfSSL · wolfSSL
before 5.8.4 · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-12888
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-12888
Broken Link
https://https://github.com/wolfSSL/wolfssl/pull/9275
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