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.

Weakness

The product subtracts one value from another, such that the result is less than the minimum allowable integer value, which produces a value that is not equal to the correct result.

Affected Software

References

• https://github.com/strongswan/strongswan/commits/master/src/libcharon/plugins/eap_mschapv2
• https://github.com/strongswan/strongswan/releases
• https://www.strongswan.org/blog/2025/10/27/strongswan-vulnerability-%28cve-2025-62291%29.html
• https://lists.debian.org/debian-lts-announce/2025/11/msg00002.html