Integer underflow in strongSwan
Priority LOW 39CWE-191Published · Updated
Key facts
- Attack vector
- Network
- Privileges required
- None
- User interaction
- None
- Attack complexity
- High
- Impact type
- Code execution
- Confidentiality · integrity · availability
- High · High · High
- Fix status
- Fixed
Attack profile from CVSS 3.1 · CNA. Fix status from CNA. Impact type from CWE-191 and the CVSS impact.
Summary
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.
Why it matters now
Exploitation None reported CISA SSVC · not in CISA KEV
EPSS 0.00983 62nd percentileScored 2026-11-07
Fix Fixed strongSwan (strongSwan): 6.0.3
SSVC decision points
CISA ADP · SSVC 2.0.3
- Exploitation
- None
- Automatable
- No
- Technical impact
- Total
The decision (Track, Attend, Act) also depends on your mission and well-being impact; see CISA's SSVC guide.
Affected products
| Vendor | Product | Affected versions | Fixed in | Status | Source |
|---|---|---|---|---|---|
| strongSwan | strongSwan | 4.2.12 to before 6.0.3 | 6.0.3 | Patch available | CNA |
- strongSwan VendorstrongSwan Affected 4.2.12 to before 6.0.3 Fixed in 6.0.3 Patch available CNA
CPE names Threatist (inferred) · 1
Inferred from how NVD named this product before; not given by a source.
| CPE | Versions | Role | Vendor |
|---|---|---|---|
| cpe:2.3:a:strongswan:strongswan:*:*:*:*:*:*:*:* | — | — | strongSwan |
- cpe:2.3:a:strongswan:strongswan:*:*:*:*:*:*:*:* Versions — — ·strongSwan
Remediation
- Fix · CNA strongSwan (strongSwan) Fixed in 6.0.3
Vendor assessments
Timeline
- 2026-10-02 Threatist record created from CVE-2025-62291
- 2026-10-03 Alias added: GHSA-p527-wjvq-vxg8
References
More strongSwan vulnerabilities
- TI-2023-22300 strongSwan before 5.9.12 has a buffer overflow and possible unauthenticated remote code… CVSS 3.1CRITICAL 9.8
- TI-2015-03374 strongSwan 5.2.2 and 5.3.0 allows remote attackers to cause a denial of service (daemon… CVSS 3.0CRITICAL 9.8
- TI-2004-00531 FreeS/WAN 1.x and 2.x, and other related products including superfreeswan 1.x, openswan… CVSS 2.0HIGH 10.0
- TI-2026-20255 strongSwan 4.5.0 < 6.0.5 EAP-TTLS AVP Parsing Integer Underflow CVSS 4.0HIGH 8.7
- TI-2023-11610 strongSwan 5.9.8 and 5.9.9 potentially allows remote code execution because it uses a… CVSS 3.1CRITICAL 9.8
- TI-2026-21012 strongMan vulnerable to private credential recovery due to key and counter reuse CVSS 4.0HIGH 8.7
Sources
- CVE-2025-62291 · CVE Program
- CVE-2025-62291 · NVD
- FIRST EPSS
- GHSA-p527-wjvq-vxg8 · GitHub Advisory Database · CC BY 4.0
- CVE-2025-62291 · Red Hat security data · CC BY 4.0
This product uses the NVD API but is not endorsed or certified by the NVD. Sources and licences