High severity · published Jan 16, 2026
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…
8.1
CVSS
1%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H
Attack vector
Network
Complexity
High
Privileges
None
User interaction
None
Confidentiality
High
Integrity
High
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)1.0% · higher than 62% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
ST
strongSwan · strongSwan
4.2.12 before 6.0.3 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2025-62291
CVE.org
https://www.cve.org/CVERecord?id=CVE-2025-62291
github.com
https://github.com/strongswan/strongswan/commits/master/src/libcharon/plugins/eap_mschapv2
github.com
https://github.com/strongswan/strongswan/releases
www.strongswan.org
https://www.strongswan.org/blog/2025/10/27/strongswan-vulnerability-%28cve-2025-62291%29.html
lists.debian.org
https://lists.debian.org/debian-lts-announce/2025/11/msg00002.html
More from strongSwan
9.8
CVE-2023-41913
strongSwan before 5.9.12 has a buffer overflow and possible unauthenticated remote code execution via a DH public value that exceeds the internal buffer in charon-tkm's DH proxy
9.8
CVE-2023-26463
strongSwan 5.9.8 and 5.9.9 potentially allows remote code execution because it uses a variable named "public" for two different purposes within the same function
9.8
CVE-2015-3991
strongSwan 5.2.2 and 5.3.0 allows remote attackers to cause a denial of service (daemon crash) or execute arbitrary code
9.1
CVE-2021-45079
In strongSwan before 5.9.5, a malicious responder can send an EAP-Success message too early without actually authenticating the client and (in the case of EAP methods with mutual…
7.5
CVE-2026-78133
libcharon in strongSwan 6.0.0 through 6.0.7 has a use-after-free in IKEv2 rekeying collision handling