In-memory file operations (ie: using fopen on a data URI) did not properly restrict negative seeking, allowing for the reading of memory prior to the in-memory buffer. 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.
Source: https://cve.mitre.org/cgi-bin/cvename.cgi?name=CVE-2020-1918
Reference (s):
- https://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44ca
- URL: https://github.com/facebook/hhvm/commit/08193b7f0cd3910256e00d599f0f3eb2519c44ca
- https://hhvm.com/blog/2021/02/25/security-update.html
- URL: https://hhvm.com/blog/2021/02/25/security-update.html