CVE-2019-3556
8.1 · HIGHOverview
CVE-2019-3556 is a high-severity vulnerability affecting facebook hhvm. It was published on October 26, 2021 and has a CVSS 3.1 base score of 8.1 (HIGH).
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
Technical Description
HHVM supports the use of an "admin" server which accepts administrative requests over HTTP. One of those request handlers, dump-pcre-cache, can be used to output cached regular expressions from the current execution context into a file. The handler takes a parameter which specifies where on the filesystem to write this data. The parameter is not validated, allowing a malicious user to overwrite arbitrary files where the user running HHVM has write access. This issue affects HHVM versions prior to 4.56.2, all versions between 4.57.0 and 4.78.0, as well as 4.79.0, 4.80.0, 4.81.0, 4.82.0, and 4.83.0.
Remediation
Check the references section for vendor advisories and patches from facebook. Update hhvm to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
Affected Products
| Vendor | Product | Versions | Status |
|---|---|---|---|
| hhvm | >= 0, < 4.56.2 | Affected |
References
Frequently Asked Questions
What is CVE-2019-3556?
CVE-2019-3556 is a high-severity vulnerability affecting facebook hhvm. It was published on October 26, 2021 and has a CVSS 3.1 base score of 8.1 (HIGH).
How severe is CVE-2019-3556?
This vulnerability has a CVSS 3.1 base score of 8.1, rated HIGH. It can be exploited remotely over the network. Some level of privileges is required for exploitation.
How do I fix or remediate CVE-2019-3556?
Check the references section for vendor advisories and patches from facebook. Update hhvm to the latest patched version. If immediate patching is not possible, review the CVSS vector to understand the attack surface and apply compensating controls such as network segmentation or access restrictions.
How can CyberStrike help with CVE-2019-3556?
CyberStrike's AI-powered security agents can automatically detect CVE-2019-3556 across your infrastructure using autonomous pentesting, DAST scanning, and HackBrowser. The platform continuously monitors for known vulnerabilities and provides actionable remediation guidance prioritized by real-world exploitability.
How CyberStrike Helps
AI agents map your attack surface to find vulnerabilities like this one.
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