Multiple vulnerabilities in Microsoft Exchange Server
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 4 |
| CVE-ID | CVE-2021-26427 CVE-2021-34453 CVE-2021-41348 CVE-2021-41350 |
| CWE-ID | CWE-264 CWE-20 CWE-79 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software Subscribe |
Microsoft Exchange Server Server applications / Mail servers |
| Vendor | Microsoft |
Security Bulletin
This security bulletin contains information about 4 vulnerabilities.
1) Security restrictions bypass
EUVDB-ID: #VU57255
Risk: Medium
CVSSv3.1: 7.8 [CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-26427
CWE-ID:
CWE-264 - Permissions, Privileges, and Access Controls
Exploit availability: No
DescriptionThe vulnerability allows a remote user to escalate privileges on the system.
The vulnerability exists due to application does not properly impose security restrictions. A remote user on the local network can send specially crafted data to the Exchange server and execute arbitrary code with elevated privileges.
Install updates from vendor's website.
Vulnerable software versionsMicrosoft Exchange Server: 2013 Cumulative Update 1 15.00.0712.024 - 2019 RTM 15.02.0221.012
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-26427
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
2) Input validation error
EUVDB-ID: #VU57254
Risk: Medium
CVSSv3.1: 6.5 [CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-34453
CWE-ID:
CWE-20 - Improper input validation
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to insufficient validation of user-supplied input. A remote attacker can send specially crafted input to the server and perform a denial of service (DoS) attack.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMicrosoft Exchange Server: 2016 Cumulative Update 1 15.01.0396.030 - 2019 RTM 15.02.0221.012
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-34453
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
3) Security restrictions bypass
EUVDB-ID: #VU57252
Risk: Medium
CVSSv3.1: 6.4 [CVSS:3.1/AV:A/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-41348
CWE-ID:
CWE-264 - Permissions, Privileges, and Access Controls
Exploit availability: No
DescriptionThe vulnerability allows a remote user to escalate privileges on the system.
The vulnerability exists due to application does not properly impose security restrictions, which leads to security restrictions bypass and privilege escalation.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMicrosoft Exchange Server: 2016 Cumulative Update 1 15.01.0396.030 - 2019 RTM 15.02.0221.012
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-41348
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote authenticated user via the local network (LAN).
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
4) Cross-site scripting
EUVDB-ID: #VU57251
Risk: Medium
CVSSv3.1: 5.3 [CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N/E:U/RL:O/RC:C]
CVE-ID: CVE-2021-41350
CWE-ID:
CWE-79 - Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Exploit availability: No
DescriptionThe disclosed vulnerability allows a remote attacker to perform cross-site scripting (XSS) attacks.
The vulnerability exists due to insufficient sanitization of user-supplied data. A remote attacker can trick the victim to follow a specially crafted link and execute arbitrary HTML and script code in user's browser in context of vulnerable website.
Successful exploitation of this vulnerability may allow a remote attacker to steal potentially sensitive information, change appearance of the web page, perform spoofing attacks.
MitigationInstall updates from vendor's website.
Vulnerable software versionsMicrosoft Exchange Server: 2016 Cumulative Update 1 15.01.0396.030 - 2019 RTM 15.02.0221.012
External linkshttp://portal.msrc.microsoft.com/en-US/security-guidance/advisory/CVE-2021-41350
Q & A
Can this vulnerability be exploited remotely?
Yes. This vulnerability can be exploited by a remote non-authenticated attacker via the Internet.
How the attacker can exploit this vulnerability?
The attacker would have to send a specially crafted request to the affected application in order to exploit this vulnerability.
Is there known malware, which exploits this vulnerability?
No. We are not aware of malware exploiting this vulnerability.
