Buffer overflow in Facebook Hhvm

CVE-2020-1899

The unserialize() function supported a type code, "S", which was meant to be supported only for APC serialization. This type code allowed arbitrary memory addresses to be accessed as if they were static StringData objects. This issue affected HHVM prior to v4.32.3, between versions 4.33.0 and 4.56.0, 4.57.0, 4.58.0, 4.58.1, 4.59.0, 4.60.0, 4.61.0, 4.62.0.

EPSS: 0.012 (65.5th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N.

Affected products

Weakness classification (CWE)

References

Frequently asked questions

What is CVE-2020-1899?
CVE-2020-1899 is a high-severity vulnerability in Facebook Hhvm, classified under Untrusted Pointer Dereference. CVSS score: 7.5/10. Published 2021-03-11.
How severe is CVE-2020-1899?
High severity. CVSS v3 base score is 7.5 out of 10.