VDB-174828 · CVE-2021-26421 · GCVE-0-2021-26421

Microsoft Lync Server/Skype for Business Server 2013 CU10/2015 CU11 privilege escalation

CVSS Meta Temp Score CVSS is a standardized scoring system to determine possibilities of attacks. The Temp Score considers temporal factors like disclosure, exploit and countermeasures. The unique Meta Score calculates the average score of different sources to provide a normalized scoring system.	Current Exploit Price (≈) Our analysts are monitoring exploit markets and are in contact with vulnerability brokers. The range indicates the observed or calculated exploit price to be seen on exploit markets. A good indicator to understand the monetary effort required for and the popularity of an attack.	CTI Interest Score Our Cyber Threat Intelligence team is monitoring different web sites, mailing lists, exploit markets and social media networks. The CTI Interest Score identifies the interest of attackers and the security community for this specific vulnerability in real-time. A high score indicates an elevated risk to be targeted for this vulnerability.
5.2	$0-$5k	0.00

Summaryinfo

A vulnerability labeled as problematic has been found in Microsoft Lync Server and Skype for Business Server 2013 CU10/2015 CU11. Impacted is an unknown function. The manipulation results in an unknown weakness. This vulnerability was named CVE-2021-26421. The attack may be performed from remote. There is no available exploit. It is advisable to implement a patch to correct this issue.

Detailsinfo

A vulnerability, which was classified as problematic, was found in Microsoft Lync Server and Skype for Business Server 2013 CU10/2015 CU11 (Unified Communication Software). This is going to have an impact on confidentiality, integrity, and availability.

The weakness was presented 05/11/2021 as confirmed security guidance (Website). The advisory is shared for download at portal.msrc.microsoft.com. This vulnerability is traded as CVE-2021-26421. Successful exploitation requires user interaction by the victim. There are neither technical details nor an exploit publicly available.

Applying a patch is able to eliminate this problem. A possible mitigation has been published immediately after the disclosure of the vulnerability.

Once again VulDB remains the best source for vulnerability data.

Productinfo

Type

Unified Communication Software

Vendor

Microsoft

Name

Version

License

commercial

Website

Vendor: https://www.microsoft.com/

CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔍
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 6.0
VulDB Meta Temp Score: 5.2

VulDB Base Score: 5.5
VulDB Temp Score: 4.8
VulDB Vector: 🔍
VulDB Reliability: 🔍

Vendor Base Score (Microsoft): 6.5
Vendor Vector (Microsoft): 🔍

CVSSv2info

AV	AC	Au	C	I	A
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳
💳	💳	💳	💳	💳	💳

Vector	Complexity	Authentication	Confidentiality	Integrity	Availability
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock
Unlock	Unlock	Unlock	Unlock	Unlock	Unlock

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

Exploitinginfo

Class: Privilege escalation
CWE: Unknown
CAPEC: 🔍
ATT&CK: 🔍

Physical: No
Local: No
Remote: Yes

Availability: 🔍
Status: Unproven

EPSS Score: 🔍
EPSS Percentile: 🔍

Price Prediction: 🔍
Current Price Estimation: 🔍

0-Day	Unlock	Unlock	Unlock	Unlock
Today	Unlock	Unlock	Unlock	Unlock

Threat Intelligenceinfo

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

Countermeasuresinfo

Recommended: Patch
Status: 🔍

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

Timelineinfo

01/29/2021 🔍
05/11/2021 +102 days 🔍
05/11/2021 +0 days 🔍
05/12/2021 +0 days 🔍
05/13/2021 +1 days 🔍

Sourcesinfo

Vendor: microsoft.com

Advisory: portal.msrc.microsoft.com
Status: Confirmed

CVE: CVE-2021-26421 (🔍)
GCVE (CVE): GCVE-0-2021-26421
GCVE (VulDB): GCVE-100-174828
scip Labs: https://www.scip.ch/en/?labs.20140918

Entryinfo

Created: 05/12/2021 02:06
Updated: 05/13/2021 11:32
Changes: 05/12/2021 02:06 (32), 05/12/2021 02:10 (21), 05/13/2021 11:32 (2)
Complete: 🔍
Cache ID: 216::103