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CVE-2023-26463

32
FAUCET Score

CVE-2023-26463 is a critical remote code execution vulnerability affecting strongSwan versions 5.9.8 and 5.9.9, stemming from a variable reuse error and subsequent expired pointer dereference. This flaw, with a CVSS score of 9.8, allows unauthenticated attackers to achieve full compromise (confidentiality, integrity, availability) by sending a crafted client certificate during EAP-TLS, specifically impacting servers configured with TLS-based EAP methods. While there is no evidence of active exploitation or public exploit code (Metasploit, Nuclei, ExploitDB), the vulnerability has garnered significant community attention, with 11 mentions and a high EPSS score, indicating a higher-than-average likelihood of future exploitation. A patch is available in strongSwan 5.9.10.

Impacted Technologies

VendorProductVersion(s)CPE
5.9.8CPE matchmatch criteria
cpe:2.3:a:strongswan:strongswan:5.9.8:-:*:*:*:*:*:*
5.9.9CPE matchmatch criteria
cpe:2.3:a:strongswan:strongswan:5.9.9:-:*:*:*:*:*:*

CVSS Data

CVSS version used by this source: 3.1

9.8CRITICAL

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

Attack Vector
NETWORK
Attack Complexity
LOW
Privileges Required
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality Impact
HIGH
Integrity Impact
HIGH
Availability Impact
HIGH
Exploitability Score
3.9
Impact Score
5.9
CvssVersion
3.1

Exploit Intelligence

EPSS Score
2.28%
Probability of exploitation in next 30 days
EPSS Percentile
81.4%
Percentile rank of EPSS score among Peer Group
As of 2026-07-28
Model: v2026.06.15
This CVE's current EPSS score of 0.0228 is in the 71st percentile among its peer group of 36,897 CVEs.

Social Chatter

The average CVE in this peer group has 0.0 Twitter, 0.1 Reddit, 0.3 Bluesky, 0.3 Mastodon, and 2.4 GitHub mentions.

Media Mentions

The average CVE in this peer group has 0.3 InfoSec Media, 0.0 Vendor Blog, and 0.0 Security Researcher mentions.

Remediation

Patch Available

Vendor Patches (4)

microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 x64Fixed in: 5.9.10-1
microsoftpatch availablevia msrc
Product: CBL Mariner 2.0 ARMFixed in: 5.9.10-1
microsoftpatch availablevia msrc
Product: cbl2 strongswan 5.9.10-1 on CBL Mariner 2.0Fixed in: 5.9.10-1
microsoftpatch availablevia msrc
Product: 18378-16823Fixed in: 5.9.10-1

Vendor Advisories (2)

microsoft2023-May/CVE-2023-26463

CVE-2023-26463

May 9, 2023
microsoft2023-Apr/CVE-2023-26463Critical

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.

Apr 11, 2023

References

github.com / strongswan/strongswan/releases
Release Notes
security.netapp.com / advisory/ntap-20230517-0010
strongswan.org / blog/2023/03/02/strongswan-vulnerability-%28cve-2023-26463%29.html
MitigationVendor Advisory