X.Org Server up to 1.19.3 Shared Memory Segments access control

CVSS Meta Temp Score
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CTI Interest Score
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4.5$0-$5k0.00

Summaryinfo

A vulnerability labeled as critical has been found in X.Org Server up to 1.19.3. This impacts an unknown function of the component Shared Memory Segments. Such manipulation leads to access control. This vulnerability is referenced as CVE-2017-13721. The attack can only be performed from a local environment. No exploit is available. Applying a patch is advised to resolve this issue.

Detailsinfo

A vulnerability was found in X.Org Server up to 1.19.3 and classified as critical. Affected by this issue is an unknown part of the component Shared Memory Segments. The manipulation with an unknown input leads to a access control vulnerability. Using CWE to declare the problem leads to CWE-264. Impacted is confidentiality, integrity, and availability. CVE summarizes:

In X.Org Server (aka xserver and xorg-server) before 1.19.4, an attacker authenticated to an X server with the X shared memory extension enabled can cause aborts of the X server or replace shared memory segments of other X clients in the same session.

The bug was discovered 10/04/2017. The weakness was published 10/10/2017 (oss-sec). The advisory is shared for download at openwall.com. This vulnerability is handled as CVE-2017-13721 since 08/28/2017. The attack needs to be approached locally. No form of authentication is required for exploitation. There are neither technical details nor an exploit publicly available. The MITRE ATT&CK project declares the attack technique as T1068.

The vulnerability was handled as a non-public zero-day exploit for at least 5 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 103882 (Debian DSA-4000-1 : xorg-server - security update), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Debian Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 176180 (Debian Security Update for xorg-server (DSA 4000-1)).

Upgrading to version 1.19.4 eliminates this vulnerability. Applying a patch is able to eliminate this problem. The bugfix is ready for download at cgit.freedesktop.org. The best possible mitigation is suggested to be patching the affected component. A possible mitigation has been published 1 weeks after the disclosure of the vulnerability.

The vulnerability is also documented in the databases at Tenable (103882) and SecurityFocus (BID 101238†). Similar entry is available at VDB-107601. VulDB is the best source for vulnerability data and more expert information about this specific topic.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.6
VulDB Meta Temp Score: 4.5

VulDB Base Score: 4.5
VulDB Temp Score: 4.3
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 4.7
NVD Vector: 🔍

CVSSv2info

AVACAuCIA
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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
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NVD Base Score: 🔍

Exploitinginfo

Class: Access control
CWE: CWE-264
CAPEC: 🔍
ATT&CK: 🔍

Physical: Partially
Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 103882
Nessus Name: Debian DSA-4000-1 : xorg-server - security update
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

OpenVAS ID: 53379
OpenVAS Name: Debian Security Advisory DSA 4000-1 (xorg-server - security update)
OpenVAS File: 🔍
OpenVAS Family: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
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Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Patch
Status: 🔍

Reaction Time: 🔍
0-Day Time: 🔍
Exposure Time: 🔍

Upgrade: X.Org Server 1.19.4
Patch: cgit.freedesktop.org

Timelineinfo

08/28/2017 🔍
10/04/2017 +37 days 🔍
10/04/2017 +0 days 🔍
10/09/2017 +5 days 🔍
10/10/2017 +1 days 🔍
10/10/2017 +0 days 🔍
10/17/2017 +7 days 🔍
10/18/2017 +1 days 🔍
08/29/2025 +2872 days 🔍

Sourcesinfo

Advisory: openwall.com
Status: Confirmed
Confirmation: 🔍

CVE: CVE-2017-13721 (🔍)
GCVE (CVE): GCVE-0-2017-13721
GCVE (VulDB): GCVE-100-107600

OVAL: 🔍

SecurityFocus: 101238 - X.Org X Server CVE-2017-13721 Local Security Bypass Vulnerability

See also: 🔍

Entryinfo

Created: 10/10/2017 10:02
Updated: 08/29/2025 16:04
Changes: 10/10/2017 10:02 (78), 11/23/2019 08:13 (4), 08/29/2025 16:04 (19)
Complete: 🔍
Cache ID: 216::103

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