xkbcommon up to 0.8.0 Keymap File xkbcomp/ast-build.c use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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5.5$0-$5k0.00

A vulnerability, which was classified as problematic, has been found in xkbcommon up to 0.8.0. Affected by this issue is some unknown processing of the file xkbcomp/ast-build.c of the component Keymap File Handler. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is availability. CVE summarizes:

An invalid free in ExprAppendMultiKeysymList in xkbcomp/ast-build.c in xkbcommon before 0.8.1 could be used by local attackers to crash xkbcommon keymap parsers or possibly have unspecified other impact by supplying a crafted keymap file.

The bug was discovered 08/03/2018. The weakness was presented 08/25/2018 (Website). The advisory is shared for download at github.com. This vulnerability is handled as CVE-2018-15857 since 08/24/2018. The exploitation is known to be easy. The attack needs to be approached locally. No form of authentication is required for exploitation. There are known technical details, but no exploit is available.

The vulnerability was handled as a non-public zero-day exploit for at least 22 days. During that time the estimated underground price was around $0-$5k. The vulnerability scanner Nessus provides a plugin with the ID 118505 (GLSA-201810-05 : xkbcommon: Multiple vulnerabilities), which helps to determine the existence of the flaw in a target environment. It is assigned to the family Gentoo Local Security Checks and running in the context l. The commercial vulnerability scanner Qualys is able to test this issue with plugin 197271 (Ubuntu Security Notification for Libxkbcommon Vulnerabilities (USN-3786-1)).

Upgrading to version 0.8.1 eliminates this vulnerability. A possible mitigation has been published 3 months after the disclosure of the vulnerability.

The vulnerability is also documented in the vulnerability database at Tenable (118505). See 123244, 123245, 123246 and 123247 for similar entries.

Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB CVSS-B Score: 🔍
VulDB CVSS-BT Score: 🔍
VulDB Vector: 🔍
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CVSSv3info

VulDB Meta Base Score: 5.5
VulDB Meta Temp Score: 5.5

VulDB Base Score: 3.3
VulDB Temp Score: 3.2
VulDB Vector: 🔍
VulDB Reliability: 🔍

NVD Base Score: 7.8
NVD Vector: 🔍

CVSSv2info

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VulDB Base Score: 🔍
VulDB Temp Score: 🔍
VulDB Reliability: 🔍

NVD Base Score: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
ATT&CK: Unknown

Local: Yes
Remote: No

Availability: 🔍
Status: Not defined

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

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Nessus ID: 118505
Nessus Name: GLSA-201810-05 : xkbcommon: Multiple vulnerabilities
Nessus File: 🔍
Nessus Risk: 🔍
Nessus Family: 🔍
Nessus Context: 🔍

Qualys ID: 🔍
Qualys Name: 🔍

Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

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

Upgrade: xkbcommon 0.8.1
Patch: github.com

Timelineinfo

08/03/2018 🔍
08/24/2018 +20 days 🔍
08/25/2018 +1 days 🔍
08/25/2018 +0 days 🔍
08/26/2018 +1 days 🔍
10/30/2018 +65 days 🔍
10/31/2018 +1 days 🔍
05/04/2023 +1646 days 🔍

Sourcesinfo

Advisory: RHSA-2019:2079
Status: Confirmed

CVE: CVE-2018-15857 (🔍)
See also: 🔍

Entryinfo

Created: 08/26/2018 08:58
Updated: 05/04/2023 14:57
Changes: 08/26/2018 08:58 (73), 03/18/2020 10:32 (2), 05/04/2023 14:57 (5)
Complete: 🔍

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