CVE-2019-11930

An invalid free in mb_detect_order can cause the application to crash or potentially result in remote code execution. This issue affects HHVM versions prior to 3.30.12, all versions between 4.0.0 and 4.8.5, all versions between 4.9.0 and 4.23.1, as well as 4.24.0, 4.25.0, 4.26.0, 4.27.0, 4.28.0, and 4.28.1.

Weakness

The product attempts to return a memory resource to the system, but it calls the wrong release function or calls the appropriate release function incorrectly.

Affected Software

Extended Description

This weakness can take several forms, such as:

Potential Mitigations

• Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid.
• For example, glibc in Linux provides protection against free of invalid pointers.

References

• https://github.com/facebook/hhvm/commit/524d2e60cfe910406ec6109e4286d7edd545ab36
• https://hhvm.com/blog/2019/10/28/security-update.html
• https://www.facebook.com/security/advisories/cve-2019-11930