CVE-2016-4538
php: bcpowmod accepts negative scale causing heap buffer overflow corrupting _one_ definition
Severity
LowRed Hat Product Security
CVSS 2.0
Review impact separately from score.
Published · April 24, 2016
Updated · June 28, 2026
Description
The bcpowmod function in ext/bcmath/bcmath.c in PHP before 5.5.35, 5.6.x before 5.6.21, and 7.x before 7.0.6 modifies certain data structures without considering whether they are copies of the zero, one, or two global variable, which allows remote attackers to cause a denial of service or possibly have unspecified other impact via a crafted call.
CVSS score applicability
The CVSS score(s) listed for this vulnerability do not reflect the associated product's status, and are included for informational purposes to better understand the severity of this vulnerability.
Mitigation
No mitigation is specified in collected source.
CVSS / CWE
CVSS 2.0 · 2.6AV:N/AC:H/Au:N/C:N/I:P/A:N
CWE-122 · Heap-based Buffer Overflow