#VU14503 Off-by-one error in Xlib - CVE-2018-14599

Vulnerability identifier: #VU14503

Vulnerability risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2018-14599

CWE-ID: CWE-193

Exploitation vector: Network

Exploit availability: No

Vulnerable software:
Xlib
Universal components / Libraries / Libraries used by multiple products

Vendor: X.org

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to an off-by-one memory write error in the XGetFontPath(), XListExtensions(), and XListFonts() functions. A remote unauthenticated attacker can cause a remote X server to return a specially crafted response to trigger memory corruption and execute arbitrary code on the target X client.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation
Install update from vendor's website.

Vulnerable software versions

Xlib: 1.0.1 - 1.6.6

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External links
https://gitlab.freedesktop.org/xorg/lib/libx11/commit/b469da1430cdcee06e31c6251b83aede072a1ff0

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Q & A

Can this vulnerability be exploited remotely?

Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.

Is there known malware, which exploits this vulnerability?

No. We are not aware of malware exploiting this vulnerability.