What’s Vulnerable › Vulnerabilities

CVE-2019-11929

• Severity: critical (CVSS 9.8 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 4.0% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2019-10-02 · updated 2026-06-17
• Weakness: CWE-119

Description

Insufficient boundary checks when formatting numbers in number_format allows read/write access to out-of-bounds memory, potentially leading to remote code execution. This issue affects HHVM versions prior to 3.30.10, all versions between 4.0.0 and 4.8.5, all versions between 4.9.0 and 4.18.2, and versions 4.19.0, 4.19.1, 4.20.0, 4.20.1, 4.20.2, 4.21.0, 4.22.0, 4.23.0.

Affected products

• Facebook HHVM: before 3.30.10; from 4.0.0 through 4.8.5; from 4.9.0 through 4.18.2; 4.19.0, 4.19.1, 4.20.0, 4.20.1, 4.20.2, 4.21.0 (+2) — fixed in 3.30.10

How to fix

Upgrade to a fixed version: Facebook HHVM 3.30.10. Check the vendor advisory for mitigations.

References

• https://github.com/facebook/hhvm/commit/dbeb9a56a638e3fdcef8b691c2a2967132dae692
• https://hhvm.com/blog/2019/09/25/security-update.html
• https://www.facebook.com/security/advisories/cve-2019-11929
• https://github.com/facebook/hhvm/commit/dbeb9a56a638e3fdcef8b691c2a2967132dae692
• https://hhvm.com/blog/2019/09/25/security-update.html
• https://www.facebook.com/security/advisories/cve-2019-11929

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