Quantum Secular Labs / Blog / Advisories

CVE-2016-5114: PHP: Buffer overflow

CVE-2016-5114 is rated critical with a CVSS v3.0 base score of 9.1 and affects PHP. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

sapi/fpm/fpm/fpm_log.c in PHP before 5.5.31, 5.6.x before 5.6.17, and 7.x before 7.0.2 misinterprets the semantics of the snprintf return value, which allows attackers to obtain sensitive information from process memory or cause a denial of service (out-of-bounds read and buffer overflow) via a long string, as demonstrated by a long URI in a configuration with custom REQUEST_URI logging.

Severity breakdown

CVSS v3.0 9.1: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Attack vector: Network. Exploitable remotely over the network, with no need for local or physical access.
Attack complexity: Low. No special conditions; the attack can be repeated reliably.
Privileges required: None. No account or prior access is needed.
User interaction: None. No action from any user is needed.
Scope: Unchanged. Impact stays within the vulnerable component.
Confidentiality impact: High. Total loss of confidentiality; sensitive data can be fully disclosed.
Integrity impact: None. No loss of integrity.
Availability impact: High. Total loss of availability; the component can be shut down.

Underlying weakness

CWE-119: Improper Restriction of Operations within the Bounds of a Memory Buffer

The product performs operations on a memory buffer, but it reads from or writes to a memory location outside the buffer's intended boundary.

CWE-125: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

Affected products

PHP: up to and including 5.5.30; 5.6.0 alpha1; 5.6.0 alpha2; 5.6.0 alpha3; 5.6.0 alpha4; 5.6.0 alpha5; 5.6.0 beta1; 5.6.0 beta2; 5.6.0 beta3; 5.6.0 beta4; 5.6.1; 5.6.2