Red Hat Enterprise Linux 8 update for libvncserver
| Risk | Medium |
| Patch available | YES |
| Number of vulnerabilities | 5 |
| CVE-ID | CVE-2018-21247 CVE-2019-20839 CVE-2020-14397 CVE-2020-14405 CVE-2020-25708 |
| CWE-ID | CWE-401 CWE-119 CWE-476 CWE-770 CWE-369 |
| Exploitation vector | Network |
| Public exploit | N/A |
| Vulnerable software |
libvncserver (Red Hat package) Operating systems & Components / Operating system package or component Red Hat CodeReady Linux Builder for ARM 64 Operating systems & Components / Operating system Red Hat CodeReady Linux Builder for Power, little endian Operating systems & Components / Operating system Red Hat CodeReady Linux Builder for x86_64 Operating systems & Components / Operating system Red Hat Enterprise Linux for ARM 64 Operating systems & Components / Operating system Red Hat Enterprise Linux for Power, little endian Operating systems & Components / Operating system Red Hat Enterprise Linux for IBM z Systems Operating systems & Components / Operating system Red Hat Enterprise Linux for x86_64 Operating systems & Components / Operating system |
| Vendor | Red Hat Inc. |
Security Bulletin
This security bulletin contains information about 5 vulnerabilities.
1) Memory leak
EUVDB-ID: #VU29384
Risk: Medium
CVSSv4.0: 4.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2018-21247
CWE-ID:
CWE-401 - Missing release of memory after effective lifetime
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to gain access to sensitive information.
The vulnerability exists due memory leak within the ConnectToRFBRepeater() function in libvncclient/rfbproto.c. A remote attacker can trick the victim to connect to a malicious VNC server, trigger the memory leak and gain access to sensitive information on the client's system.
Install updates from vendor's website.
libvncserver (Red Hat package): 0.9.11-9.el8_0.2 - 0.9.11-15.el8_2.1
Red Hat CodeReady Linux Builder for ARM 64: 8.0
Red Hat CodeReady Linux Builder for Power, little endian: 8.0
Red Hat CodeReady Linux Builder for x86_64: 8.0
Red Hat Enterprise Linux for ARM 64: 8
Red Hat Enterprise Linux for Power, little endian: 8
Red Hat Enterprise Linux for IBM z Systems: 8
Red Hat Enterprise Linux for x86_64: 8.0
CPE2.3- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_0.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.3:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_arm_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_x86_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux:8.0:*:*:*:*:*:*:*
https://access.redhat.com/errata/RHSA-2021:1811
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.
2) Buffer overflow
EUVDB-ID: #VU29373
Risk: Medium
CVSSv4.0: 4.8 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2019-20839
CWE-ID:
CWE-119 - Memory corruption
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to execute arbitrary code on the target system.
The vulnerability exists due to a boundary when processing long socket filename in libvncclient/sockets.c in LibVNCServer. A remote attacker can rick the victim to connect to server using a specially crafted configuration file, trigger buffer overflow and execute arbitrary code on the target system.
Install updates from vendor's website.
libvncserver (Red Hat package): 0.9.11-9.el8_0.2 - 0.9.11-15.el8_2.1
Red Hat CodeReady Linux Builder for ARM 64: 8.0
Red Hat CodeReady Linux Builder for Power, little endian: 8.0
Red Hat CodeReady Linux Builder for x86_64: 8.0
Red Hat Enterprise Linux for ARM 64: 8
Red Hat Enterprise Linux for Power, little endian: 8
Red Hat Enterprise Linux for IBM z Systems: 8
Red Hat Enterprise Linux for x86_64: 8.0
CPE2.3- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_0.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.3:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_arm_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_x86_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux:8.0:*:*:*:*:*:*:*
https://access.redhat.com/errata/RHSA-2021:1811
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.
3) NULL pointer dereference
EUVDB-ID: #VU29382
Risk: Medium
CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2020-14397
CWE-ID:
CWE-476 - NULL Pointer Dereference
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to a NULL pointer dereference error in libvncserver/rfbregion.c. A remote attacker can perform a denial of service (DoS) attack.
MitigationInstall updates from vendor's website.
libvncserver (Red Hat package): 0.9.11-9.el8_0.2 - 0.9.11-15.el8_2.1
Red Hat CodeReady Linux Builder for ARM 64: 8.0
Red Hat CodeReady Linux Builder for Power, little endian: 8.0
Red Hat CodeReady Linux Builder for x86_64: 8.0
Red Hat Enterprise Linux for ARM 64: 8
Red Hat Enterprise Linux for Power, little endian: 8
Red Hat Enterprise Linux for IBM z Systems: 8
Red Hat Enterprise Linux for x86_64: 8.0
CPE2.3- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_0.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.3:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_arm_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_x86_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux:8.0:*:*:*:*:*:*:*
https://access.redhat.com/errata/RHSA-2021:1811
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.
4) Allocation of Resources Without Limits or Throttling
EUVDB-ID: #VU29374
Risk: Medium
CVSSv4.0: 2.1 [CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2020-14405
CWE-ID:
CWE-770 - Allocation of Resources Without Limits or Throttling
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists in libvncclient/rfbproto.c due to LibVNCServer does not limit TextChat size.A remote attacker who controls a malicious VNC server can send large amounts of data to the client application and perform a denial of service (DoS) attack.
Install updates from vendor's website.
libvncserver (Red Hat package): 0.9.11-9.el8_0.2 - 0.9.11-15.el8_2.1
Red Hat CodeReady Linux Builder for ARM 64: 8.0
Red Hat CodeReady Linux Builder for Power, little endian: 8.0
Red Hat CodeReady Linux Builder for x86_64: 8.0
Red Hat Enterprise Linux for ARM 64: 8
Red Hat Enterprise Linux for Power, little endian: 8
Red Hat Enterprise Linux for IBM z Systems: 8
Red Hat Enterprise Linux for x86_64: 8.0
CPE2.3- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_0.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.3:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_arm_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_x86_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux:8.0:*:*:*:*:*:*:*
https://access.redhat.com/errata/RHSA-2021:1811
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.
5) Division by zero
EUVDB-ID: #VU48699
Risk: Medium
CVSSv4.0: 6.6 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:U/U:Green]
CVE-ID: CVE-2020-25708
CWE-ID:
CWE-369 - Divide By Zero
Exploit availability: No
DescriptionThe vulnerability allows a remote attacker to perform a denial of service (DoS) attack.
The vulnerability exists due to divide by zero error when processed by the VNC server, would lead to a floating point exception, resulting in a denial of service. A remote attacker can pass specially crafted file to the application and crash it.
MitigationInstall updates from vendor's website.
libvncserver (Red Hat package): 0.9.11-9.el8_0.2 - 0.9.11-15.el8_2.1
Red Hat CodeReady Linux Builder for ARM 64: 8.0
Red Hat CodeReady Linux Builder for Power, little endian: 8.0
Red Hat CodeReady Linux Builder for x86_64: 8.0
Red Hat Enterprise Linux for ARM 64: 8
Red Hat Enterprise Linux for Power, little endian: 8
Red Hat Enterprise Linux for IBM z Systems: 8
Red Hat Enterprise Linux for x86_64: 8.0
CPE2.3- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_0.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.2:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:libvncserver_redhat_package:0.9.11-9.el8_1.3:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_arm_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_power_little_endian:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_codeready_linux_builder_for_x86_64:8.0:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_arm_64:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_power_little_endian:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux_for_ibm_z_systems:8:*:*:*:*:red_hat_enterprise_linux:*:*
- cpe:2.3:o:red_hat:red_hat_enterprise_linux:8.0:*:*:*:*:*:*:*
https://access.redhat.com/errata/RHSA-2021:1811
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.
