Strongswan: Improper Certificate Validation
CVE-2023-26463 is a critical-severity improper certificate validation vulnerability in Strongswan, with a CVSS 3.1 base score of 9.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Strongswan versions: 5.9.8; 5.9.9. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 2.26% chance of exploitation within 30 days, higher than 83% of scored CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Check which version of Strongswan you run against the affected versions below, and install the vendor's latest release.
- Read the advisory on strongswan.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Strongswan | Strongswan | 5.9.8; 5.9.9 | Not stated |
Version data comes from NVD's product matching. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 9.8 | Critical | NVD |
| CVSS 3.1 | 9.8 | Critical | CISA (ADP) |
Official description
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. There is initially incorrect access control, later followed by an expired pointer dereference. One attack vector is sending an untrusted client certificate during EAP-TLS. A server is affected only if it loads plugins that implement TLS-based EAP methods (EAP-TLS, EAP-TTLS, EAP-PEAP, or EAP-TNC). This is fixed in 5.9.10.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Improper Certificate Validation
The product does not validate, or incorrectly validates, a certificate.
How developers prevent this class of flaw
- Certificates should be carefully managed and checked to assure that data are encrypted with the intended owner's public key.
- If certificate pinning is being used, ensure that all relevant properties of the certificate are fully validated before the certificate is pinned, including the hostname.
More Improper Certificate Validation vulnerabilities (CWE-295)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Patches and release notes
- github.com/strongswan/strongswan/releasesRelease Notes
Other references
Other vulnerabilities in Strongswan
- 7.3 High severity
- 7.1 High severity
- 7.5 High severity
- 7.5 High severity
- 8.1 High severity
- 9.8 Critical severity
Recent Improper Certificate Validation vulnerabilities
- 8.1 High severity
- 8.8 High severity
- 9.8 Critical severity
- 7.8 High severity
Android Framework Privilege Escalation Exploited
- 7.5 High severity
- 8.1 High severity
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