Integer overflow in Strongswan

CVE-2025-62291

In the eap-mschapv2 plugin (client-side) in strongSwan before 6.0.3, a malicious EAP-MSCHAPv2 server can send a crafted message of size 6 through 8, and cause an integer underflow that potentially results in a heap-based buffer overflow.

Published · last modified .

CVSS v3 metric

CVSS v3 base score 8.1 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.010 (61.4th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 61st percentile — 61.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-62291: held from 0.009 to 0.010.

EPSS over last 30 days · oldest: 0.009 · newest: 0.010 · change: +0.001

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2025-62291?
CVE-2025-62291 is a high-severity vulnerability in Strongswan, classified under Integer Underflow. CVSS score: 8.1/10. Published 2026-01-16.
How severe is CVE-2025-62291?
High severity. CVSS v3 base score is 8.1 out of 10.