Quantum Secular Labs / Blog / Advisories

CVE-2017-7753: Mozilla Firefox: Memory corruption

CVE-2017-7753 is rated critical with a CVSS v3.0 base score of 9.1 and affects Mozilla Firefox, along with 7 other products in NVD’s configuration data. Per its scoring, it can be exploited over the network, without authentication, without any user interaction.

Vulnerability description

An out-of-bounds read occurs when applying style rules to pseudo-elements, such as ::first-line, using cached style data. This vulnerability affects Thunderbird < 52.3, Firefox ESR < 52.3, and Firefox < 55.

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-125: Out-of-bounds Read

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

Affected products

Mozilla Firefox: before 55.0; before 52.3.0
Mozilla Thunderbird: before 52.3.0
Debian Linux: 8.0; 9.0
Red Hat Enterprise Linux: 6.0; 7.0
Red Hat Enterprise Linux Desktop: 6.0; 7.0
Red Hat Enterprise Linux Server: 6.0; 7.0
Red Hat Enterprise Linux Server Aus: 7.3; 7.4
Red Hat Enterprise Linux Server Eus: 7.3; 7.4; 7.5
Red Hat Enterprise Linux Workstation: 6.0; 7.0