CVE-2017-18342 PyYAML insecurely deserializes YAML strings leading to arbitrary code execution

What is CVE-2017-18342?

CVE-2017-18342 is a critical unsafe deserialization vulnerability in Fedoraproject Fedora, published on 27 Jun 2018. An attacker can exploit it over the internet without logging in, with no action from the victim.

Official description

In PyYAML before 5.1, the yaml.load() API could execute arbitrary code if used with untrusted data. The load() function has been deprecated in version 5.1 and the 'UnsafeLoader' has been introduced for backward compatibility with the function.

Weakness: CWE-502

Which versions are affected by CVE-2017-18342?

3 open source packages ship an affected version, including pyyaml and PyYAML. It affects 2 products.

Products include Fedoraproject Fedora, Pyyaml Pyyaml.

How do I fix CVE-2017-18342?

Upgrade pyyaml to 5.1 or later.

Upgrade, and only deserialise data from trusted sources or with an allow-list of types. More about Unsafe deserialization.

Is CVE-2017-18342 being exploited?

There is no known exploitation of CVE-2017-18342 in the wild and no public exploit code.

Other vulnerabilities in Fedoraproject Fedora

• CVE-2024-4577 PHP-CGI OS Command Injection Exploited Critical 9.8
• CVE-2021-39226 Grafana Authentication Bypass Exploited Critical 9.8
• CVE-2019-5544 VMware ESXi and Horizon DaaS OpenSLP Heap-Based Buffer Overflow Exploited Critical 9.8
• CVE-2024-4947 Google Chromium V8 Type Confusion Exploited Critical 9.6
• CVE-2024-4671 Google Chromium Visuals Use-After-Free Exploited Critical 9.6

All Fedoraproject Fedora vulnerabilities

Sources

• CVE record
• NVD
• OSV
• GitHub advisory
• How this page is made

Also known as DEBIAN-CVE-2017-18342, GHSA-rprw-h62v-c2w7, MGASA-2019-0125, PYSEC-2018-49, UBUNTU-CVE-2017-18342, openSUSE-SU-2024:11247-1 and 2 more.