Insufficient boundary checks when processing M_SOFx markers from JPEG headers in the GD extension could allow access to out-of-bounds memory via a maliciously constructed invalid JPEG input. This issue affects HHVM versions prior to 3.30.9, all versions between 4.0.0 and 4.8.3, all versions between 4.9.0 and 4.15.2, and versions 4.16.0 to 4.16.3, 4.17.0 to 4.17.2, 4.18.0 to 4.18.1, 4.19.0, 4.20.0 to 4.20.1.
HHVM, when used with FastCGI, would bind by default to all available interfaces. This behavior could allow a malicious individual unintended direct access to the application, which could result in information disclosure. This issue affects versions 4.3.0, 4.4.0, 4.5.0, 4.6.0, 4.7.0, 4.8.0, versions 3.30.5 and below, and all versions in the 4.0, 4.1, and 4.2 series.
Insufficient boundary checks for the strrpos and strripos functions allow access to out-of-bounds memory. This affects all supported versions of HHVM (4.0.3, 3.30.4, and 3.27.7 and below).
The function number_format is vulnerable to a heap overflow issue when its second argument ($dec_points) is excessively large. The internal implementation of the function will cause a string to be created with an invalid length, which can then interact poorly with other functions. This affects all supported versions of HHVM (3.30.1 and 3.27.5 and below).