What’s Vulnerable › Vulnerabilities

CVE-2020-1919

• Severity: high (CVSS 7.5 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.2% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-03-10 · updated 2026-06-17
• Weakness: CWE-125

Description

Incorrect bounds calculations in substr_compare could lead to an out-of-bounds read when the second string argument passed in is longer than the first. This issue affects HHVM versions prior to 4.56.3, all versions between 4.57.0 and 4.80.1, all versions between 4.81.0 and 4.93.1, and versions 4.94.0, 4.95.0, 4.96.0, 4.97.0, 4.98.0.

Affected products

• Facebook HHVM: before 4.56.3; from 4.57.0 before 4.80.2; from 4.81.0 before 4.93.2; 4.94.0, 4.95.0, 4.96.0, 4.97.0, 4.98.0 — fixed in 4.56.3, 4.80.2, 4.93.2

How to fix

Upgrade to a fixed version: Facebook HHVM 4.56.3, 4.80.2, 4.93.2. Check the vendor advisory for mitigations.

References

• https://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44ca
• https://hhvm.com/blog/2021/02/25/security-update.html
• https://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44ca
• https://hhvm.com/blog/2021/02/25/security-update.html

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