CVE-2017-9023

The ASN.1 parser in strongSwan before 5.5.3 improperly handles CHOICE types when the x509 plugin is enabled, which allows remote attackers to cause a denial of service (infinite loop) via a crafted certificate.

Published: 2017-06-08 Last update: 2026-05-13 Assigner: [email protected] Source: [email protected]
NVD Status：Modified，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2017-9023 is rated Moderate Risk (60.4/100): CVSS High severity, with medium exploitation likelihood (EPSS 2.10%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2017-9023

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-05-27 1.25% 2.10% +0.85%
2 2026-05-15 0.96% 1.25% +0.29%
3 2026-04-13 — 0.96% —

Full EPSS history (16 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2017-9023

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.5 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 134c704f-9b21-4f2e-91b3-4a467353bcc0
7.5 3.0 HIGH
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:N)
Doesn’t really leak secrets in a meaningful way.
Integrity (I:N)
Data isn’t meaningfully altered or forged.
Availability (A:H)
Could take the service down hard or make it unusable for people who depend on it.
 3.9 3.6 [email protected]
4.3 2.0 MEDIUM
AV:N/AC:M/Au:N/C:N/I:N/A:P Click to expand
Access vector (AV:N)
Can be exploited remotely over network reachability.
Access complexity (AC:M)
Exploitation needs some favorable conditions, but not exceptional ones.
Authentication (AU:N)
No authentication is required.
Confidentiality impact (C:N)
No confidentiality impact.
Integrity impact (I:N)
No integrity impact.
Availability impact (A:P)
Partial availability impact.
 8.6 2.9 [email protected]

Weakness enumeration for CVE-2017-9023

OS Trackers for CVE-2017-9023

vendor priority summary link
alpine — CVE-2017-9023: 1 source package rows (strongswan); 10 state rows across 10 repos (3.10-main, 3.11-main, 3.12-main, 3.17-main, 3.18-main, 3.19-main, 3.20-main, 3.21-main, 3.22-main, edge-main); fixed 10, open 0. https://security.alpinelinux.org/vuln/CVE-2017-9023
debian not yet assigned CVE-2017-9023 not yet assigned priority: Debian including 1 source packages (strongswan), 5 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 5. https://security-tracker.debian.org/tracker/CVE-2017-9023
redhat medium — https://access.redhat.com/security/cve/CVE-2017-9023
suse medium CVE-2017-9023 severity moderate: SUSE including 70 source package names (strongswan, strongswan-4.4.0-6.35.1, …), 159 product×package rows across 41 product lines (SUSE CaaS Platform 4.0, SUSE Enterprise Storage 6, … (41 product lines)): Fixed 118, Known Not Affected 41. https://www.suse.com/security/cve/CVE-2017-9023/
ubuntu medium CVE-2017-9023 medium priority: Ubuntu including 1 source packages (strongswan), 5 status rows across 5 suites (trusty, upstream, xenial, yakkety, zesty): released 4, needs-triage 1. https://ubuntu.com/security/CVE-2017-9023

Affected software / configurations for CVE-2017-9023

Vendor Product Version Raw CPE
strongswan strongswan <= 5.5.2 cpe:2.3:a:strongswan:strongswan:*:*:*:*:*:*:*:*

References for CVE-2017-9023

cvelogic Threat Intelligence