# CVE-2017-9023: Denial of service in n/a

> Remote attackers can cause a denial of service via infinite loop in strongSwan ASN.1 parser when x509 plugin is enabled.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 8 Jun 2017
- **Updated:** 3 Dec 2025
- **Also known as:** ALPINE-CVE-2017-9023, DEBIAN-CVE-2017-9023, GHSA-3vpr-mhgf-fgjv, UBUNTU-CVE-2017-9023

## What is CVE-2017-9023?

CVE-2017-9023 is a high-severity denial of service vulnerability in n/a, published on 8 Jun 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-835 (Loop with Unreachable Exit Condition)

## Which versions are affected by CVE-2017-9023?

It affects 1 product.


Products: Strongswan Strongswan.

## How do I fix CVE-2017-9023?

Upgrade to a fixed version.

## Is CVE-2017-9023 being exploited?

There is no known exploitation of CVE-2017-9023 in the wild and no public exploit code.

## Other vulnerabilities in n/a

- [CVE-2023-41913](https://insights.sbomify.com/CVE-2023-41913/): Memory corruption in n/a (critical 9.8)
- [CVE-2023-26463](https://insights.sbomify.com/CVE-2023-26463/): Use after free in n/a (critical 9.8)
- [CVE-2015-3991](https://insights.sbomify.com/CVE-2015-3991/): Memory corruption in n/a (critical 9.8)
- [CVE-2022-4967](https://insights.sbomify.com/CVE-2022-4967/): Auth bypass in strongSwan (high 7.7)
- [CVE-2026-78130](https://insights.sbomify.com/CVE-2026-78130/): Null dereference in strongSwan (high 7.5)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2017-9023 and fix it if it is affected.

What it is: CVE-2017-9023 is a high-severity denial of service vulnerability in n/a, published on 8 Jun 2017. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2017-9023 in the wild and no public exploit code.

Affected product: n/a. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2017-9023/ (Markdown: https://insights.sbomify.com/CVE-2017-9023/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2017-9023
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2017-9023
- OSV: https://osv.dev/vulnerability/CVE-2017-9023

---
From sbomify Insights: https://insights.sbomify.com/CVE-2017-9023/
Summaries are generated and may contain mistakes; the official description above is the record.