7.5

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

Analyzed
AliasesUBUNTU-CVE-2025-12888DEBIAN-CVE-2025-12888ALPINE-CVE-2025-12888
Published 21-11-2025Last modified 08-12-2025

Vulnerability summary

CVE-2025-12888 is a high (CVSS 7.5) Observable Discrepancy vulnerability in wolfssl. EPSS estimates a 0.31% chance of exploitation in the next 30 days, higher than 23.6% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 1, physical access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
7.5/10
010
High · v3.1 (NVD)
EPSS score
0.31%
0%100%
Low · +0.02 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Timeline

  1. 21-11-2025
    PublishedVulnerability first disclosed.
  2. 08-12-2025
    Last modifiedVulnerability information updated.

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 metrics

7 scores · 5 sources · 2 versions

EPSS trend

Probability

0.31%

Chance of exploitation in the next 30 days

Percentile

24%

Versus all other CVEs

30-day change

Increase +0.02 pp

From 0.29% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: physical access, low-privilege account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Alpine1 product
  • wolfssl< 5.9.1-r0 | < 5.8.4-r0
Debian1 product
  • wolfsslAll versions (No fix recorded)
Ubuntu1 product
  • wolfsslAll versions (No fix recorded)
Wolfssl1 product

4 vendors · 4 products

References

6 links