Gentoo update for TigerVNC



Risk High
Patch available YES
Number of vulnerabilities 5
CVE-ID CVE-2019-15691
CVE-2019-15692
CVE-2019-15694
CVE-2019-15695
CVE-2020-26117
CWE-ID CWE-672
CWE-787
CWE-122
CWE-295
Exploitation vector Network
Public exploit N/A
Vulnerable software
 Gentoo Linux
Operating systems & Components / Operating system

net-misc/tigervnc
Operating systems & Components / Operating system package or component

Vendor Gentoo

Security Bulletin

This security bulletin contains information about 5 vulnerabilities.

1) Use-after-return

EUVDB-ID: #VU23905

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2019-15691

CWE-ID: CWE-672 - Operation on a Resource after Expiration or Release

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to incorrect usage of stack memory in ZRLEDecoder. If decoding routine would throw an exception, ZRLEDecoder may try to access stack variable, which has been already freed during the process of stack unwinding. A remote attacker can execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Update the affected packages.
net-misc/tigervnc to version: 1.12.0-r2

Vulnerable software versions

Gentoo Linux: All versions

net-misc/tigervnc: before 1.12.0-r2

CPE2.3 External links

https://security.gentoo.org/glsa/202407-14


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) Out-of-bounds write

EUVDB-ID: #VU23906

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2019-15692

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to incorrect value checks. A remote attacker can trigger out-of-bounds write from "CopyRectDecoder" and execute arbitrary code on the target system.

Mitigation

Update the affected packages.
net-misc/tigervnc to version: 1.12.0-r2

Vulnerable software versions

Gentoo Linux: All versions

net-misc/tigervnc: before 1.12.0-r2

CPE2.3 External links

https://security.gentoo.org/glsa/202407-14


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) Heap-based buffer overflow

EUVDB-ID: #VU23903

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2019-15694

CWE-ID: CWE-122 - Heap-based Buffer Overflow

Exploit availability: No

Description

The vulnerability allows a remote attacker to execute arbitrary code on the target system.

The vulnerability exists due to the signedness error in processing MemOutStream. A remote attacker can trigger heap-based buffer overflow from DecodeManager::decodeRect and execute arbitrary code on the target system.

Successful exploitation of this vulnerability may result in complete compromise of vulnerable system.

Mitigation

Update the affected packages.
net-misc/tigervnc to version: 1.12.0-r2

Vulnerable software versions

Gentoo Linux: All versions

net-misc/tigervnc: before 1.12.0-r2

CPE2.3 External links

https://security.gentoo.org/glsa/202407-14


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) Out-of-bounds write

EUVDB-ID: #VU23908

Risk: High

CVSSv4.0: 8.1 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N/E:U/U:Amber]

CVE-ID: CVE-2019-15695

CWE-ID: CWE-787 - Out-of-bounds write

Exploit availability: No

Description

The vulnerability allows a remote attacker to compromise vulnerable system.

The vulnerability exists due to insufficient sanitization of PixelFormat. A remote attacker can trigger out-of-bounds write from "CMsgReader::readSetCursor" and execute arbitrary code on the target system.

Mitigation

Update the affected packages.
net-misc/tigervnc to version: 1.12.0-r2

Vulnerable software versions

Gentoo Linux: All versions

net-misc/tigervnc: before 1.12.0-r2

CPE2.3 External links

https://security.gentoo.org/glsa/202407-14


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) Improper Certificate Validation

EUVDB-ID: #VU47533

Risk: Medium

CVSSv4.0: 1.2 [CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:L/VI:L/VA:N/SC:N/SI:N/SA:N/E:U/U:Green]

CVE-ID: CVE-2020-26117

CWE-ID: CWE-295 - Improper Certificate Validation

Exploit availability: No

Description

The vulnerability allows a remote attacker to perform a MitM attack.

The vulnerability exists due to improper TLS certificate validation in rfb/CSecurityTLS.cxx and rfb/CSecurityTLS.java in TigerVNC. Any previously accepted certificate will be considered trusted, meaning that the owner of a certificate could impersonate any server after a client had added an exception.

Mitigation

Update the affected packages.
net-misc/tigervnc to version: 1.12.0-r2

Vulnerable software versions

Gentoo Linux: All versions

net-misc/tigervnc: before 1.12.0-r2

CPE2.3 External links

https://security.gentoo.org/glsa/202407-14


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.



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