What’s Vulnerable › Vulnerabilities

CVE-2018-6335

• Severity: high (CVSS 7.5 v3.0)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.5% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2018-12-31 · updated 2026-06-17
• Weakness: CWE-400

Description

A Malformed h2 frame can cause 'std::out_of_range' exception when parsing priority meta data. This behavior can lead to denial-of-service. This affects all supported versions of HHVM (3.25.2, 3.24.6, and 3.21.10 and below) when using the proxygen server to handle HTTP2 requests.

Affected products

• Facebook HHVM: through 3.21.10; 3.24.6, 3.25.2

References

• https://github.com/facebook/hhvm/commit/4cb57dd753a339654ca464c139db9871fe961d56
• https://hhvm.com/blog/2018/05/04/hhvm-3.25.3.html
• https://github.com/facebook/hhvm/commit/4cb57dd753a339654ca464c139db9871fe961d56
• https://hhvm.com/blog/2018/05/04/hhvm-3.25.3.html

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