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Not in CISA KEV
HIGH severity

CVE-2020-23622 — cling-core

HIGH

CVE-2020-23622 is a high-severity (CVSS 7.5) Server-Side Request Forgery (SSRF) vulnerability in org.fourthline.cling:cling-core. 1 public exploit or proof-of-concept reference is indexed, so weaponization risk is real. The records list no fixed version yet; check the vendor advisory below and apply the mitigations in the meantime.

4thline cling uPnP protocol issue can lead to denial of service

Also known asGHSA-c438-6f6r-pg8w
Published
Updated
Affected
1 pkg
Patched
See advisory
Exploits
1 known
Exploitation data as of Nov 2, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗
1.2%probability of exploitation in next 30 days
Lower Risk0.00%
Lower risk than most CVEs67th percentile — riskier than 67% of all scored CVEsHighest risk
0.06%0.59%1.12%1.66%0.6%1.2%May 26Sep 26Nov 26

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

1 pkg affected
☕org.fourthline.cling:cling-core

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.

Description

An issue in the UPnP protocol in 4thline cling 2.0.0 through 2.1.2 allows remote attackers to cause a denial of service via an unchecked CALLBACK parameter in the request header. As of 2022, 4thline cling is no longer supported by the maintainers.

Affected Packages

1 total
EcosystemPackageVulnerable rangeFix
☕Mavenorg.fourthline.cling:cling-core≥ 2.0.0No fix

Affected Products

1 product · 1 configurations
Application
clingcling_project
≥ 2.0.0 && ≤ 2.1.2
range
Exploits & PoCs
1

Research use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.

An issue in the UPnP protocol in 4thline cling 2.0.0 through 2.1.2 allow…

github.comNVDAug 2022

Detection & mitigation playbook

Open-source dependency

  1. Detect

    Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.fourthline.cling:cling-core, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

  2. Remediation status

    The records we use list no patched version of org.fourthline.cling:cling-core for CVE-2020-23622. Check the maintainer's advisory, and where your build allows, override or pin the dependency away from the vulnerable range.

  3. Mitigate without a patch

    Restrict outbound requests from the affected component to an allowlist of hosts, block access to link-local and internal address ranges at the network layer, and require authentication on internal services so a forged request cannot reach them unauthenticated.

Frequently Asked Questions

An issue in the UPnP protocol in 4thline cling 2.0.0 through 2.1.2 allows remote attackers to cause a denial of service via an unchecked `CALLBACK` parameter in the request header. As of 2022, 4thline cling is no longer supported by the maintainers.
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CVE-2020-23622: cling-core DoS (High 7.5)