Several vulnerabilities have recently been discovered in TightVNC 1.x, an X11 based VNC server/viewer application for Windows and Unix.

CVE-2014-6053

The rfbProcessClientNormalMessage function in rfbserver.c in TightVNC server did not properly handle attempts to send a large amount of ClientCutText data, which allowed remote attackers to cause a denial of service (memory consumption or daemon crash) via a crafted message that was processed by using a single unchecked malloc.

CVE-2018-7225

rfbProcessClientNormalMessage() in rfbserver.c did not sanitize msg.cct.length, leading to access to uninitialized and potentially sensitive data or possibly unspecified other impact (e.g., an integer overflow) via specially crafted VNC packets.

CVE-2019-8287

TightVNC code contained global buffer overflow in HandleCoRREBBP macro function, which could potentially have result in code execution. This attack appeared to be exploitable via network connectivity.

(aka CVE-2018-20020/libvncserver)

CVE-2018-20021

TightVNC in vncviewer/rfbproto.c contained a CWE-835: Infinite loop vulnerability. The vulnerability allowed an attacker to consume an excessive amount of resources like CPU and RAM.

CVE-2018-20022

TightVNC's vncviewer contained multiple weaknesses CWE-665: Improper Initialization vulnerability in VNC client code that allowed attackers to read stack memory and could be abused for information disclosure.
Combined with another vulnerability, it could be used to leak stack memory layout and in bypassing ASLR.

CVE-2019-15678

TightVNC code version contained heap buffer overflow in rfbServerCutText handler, which could have potentially resulted in code execution. This attack appeared to be exploitable via network connectivity.

(partially aka CVE-2018-20748/libvnvserver)

CVE-2019-15679

TightVNC's vncviewer code contained a heap buffer overflow in InitialiseRFBConnection function, which could have potentially resulted in code execution. This attack appeared to be exploitable via network connectivity.

(partially aka CVE-2018-20748/libvnvserver)

CVE-2019-15680

TightVNC's vncviewer code contained a NULL pointer dereference in HandleZlibBPP function, which could have resulted in Denial of System (DoS). This attack appeared to be exploitable via network connectivity.

CVE-2019-15681

TightVNC contained a memory leak (CWE-655) in VNC server code, which allowed an attacker to read stack memory and could have been abused for information disclosure. Combined with another vulnerability, it could have been used to leak stack memory and bypass ASLR. This attack appeared to be exploitable via network connectivity.

For Debian 8 'Jessie', these problems have been fixed in version 1.3.9-6.5+deb8u1.

We recommend that you upgrade your tightvnc packages.

NOTE: Tenable Network Security has extracted the preceding description block directly from the DLA security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for LibVNCServer fixes the following issues :

Security issues fixed :

  - CVE-2018-15126: Fixed use-after-free in file transfer     extension (bsc#1120114)

  - CVE-2018-6307: Fixed use-after-free in file transfer     extension server code (bsc#1120115)

  - CVE-2018-20020: Fixed heap out-of-bound write inside     structure in VNC client code (bsc#1120116)

  - CVE-2018-15127: Fixed heap out-of-bounds write in     rfbserver.c (bsc#1120117)

  - CVE-2018-20019: Fixed multiple heap out-of-bound writes     in VNC client code (bsc#1120118)

  - CVE-2018-20023: Fixed information disclosure through     improper initialization in VNC Repeater client code     (bsc#1120119)

  - CVE-2018-20022: Fixed information disclosure through     improper initialization in VNC client code (bsc#1120120)

  - CVE-2018-20024: Fixed NULL pointer dereference in VNC     client code (bsc#1120121)

  - CVE-2018-20021: Fixed infinite loop in VNC client code     (bsc#1120122)

This update was imported from the SUSE:SLE-12:Update update project.

This update for LibVNCServer fixes the following issues :

Security issues fixed :

CVE-2018-15126: Fixed use-after-free in file transfer extension (bsc#1120114)

CVE-2018-6307: Fixed use-after-free in file transfer extension server code (bsc#1120115)

CVE-2018-20020: Fixed heap out-of-bound write inside structure in VNC client code (bsc#1120116)

CVE-2018-15127: Fixed heap out-of-bounds write in rfbserver.c (bsc#1120117)

CVE-2018-20019: Fixed multiple heap out-of-bound writes in VNC client code (bsc#1120118)

CVE-2018-20023: Fixed information disclosure through improper initialization in VNC Repeater client code (bsc#1120119)

CVE-2018-20022: Fixed information disclosure through improper initialization in VNC client code (bsc#1120120)

CVE-2018-20024: Fixed NULL pointer dereference in VNC client code (bsc#1120121)

CVE-2018-20021: Fixed infinite loop in VNC client code (bsc#1120122)

Note that Tenable Network Security has extracted the preceding description block directly from the SUSE security advisory. Tenable has attempted to automatically clean and format it as much as possible without introducing additional issues.

This update for LibVNCServer fixes the following issues :

Security issues fixed :

  - CVE-2018-15126: Fixed use-after-free in file transfer     extension (bsc#1120114)

  - CVE-2018-6307: Fixed use-after-free in file transfer     extension server code (bsc#1120115)

  - CVE-2018-20020: Fixed heap out-of-bound write inside     structure in VNC client code (bsc#1120116)

  - CVE-2018-15127: Fixed heap out-of-bounds write in     rfbserver.c (bsc#1120117)

  - CVE-2018-20019: Fixed multiple heap out-of-bound writes     in VNC client code (bsc#1120118)

  - CVE-2018-20023: Fixed information disclosure through     improper initialization in VNC Repeater client code     (bsc#1120119)

  - CVE-2018-20022: Fixed information disclosure through     improper initialization in VNC client code (bsc#1120120)

  - CVE-2018-20024: Fixed NULL pointer dereference in VNC     client code (bsc#1120121)

  - CVE-2018-20021: Fixed infinite loop in VNC client code     (bsc#1120122)

This update was imported from the SUSE:SLE-15:Update update project.

The remote Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-3877-1 advisory.

    It was discovered that LibVNCServer incorrectly handled certain operations. A remote attacker able to     connect to applications using LibVNCServer could possibly use this issue to obtain sensitive information,     cause a denial of service, or execute arbitrary code.

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The Linux/Unix host has one or more packages installed that are impacted by a vulnerability without a vendor supplied patch available.

  - LibVNC before 2f5b2ad1c6c99b1ac6482c95844a84d66bb52838 contains multiple weaknesses CWE-665: Improper     Initialization vulnerability in VNC client code that allows attacker to read stack memory and can be abuse     for information disclosure. Combined with another vulnerability, it can be used to leak stack memory     layout and in bypassing ASLR (CVE-2018-20022)

Note that Nessus relies on the presence of the package as reported by the vendor.

The remote Ubuntu 18.04 LTS host has packages installed that are affected by multiple vulnerabilities as referenced in the USN-4547-1 advisory.

    It was discovered that an information disclosure vulnerability existed in the LibVNCServer vendored in     iTALC when sending a ServerCutText message. An attacker could possibly use this issue to expose sensitive     information. (CVE-2019-15681)

    It was discovered that the LibVNCServer and LibVNCClient vendored in iTALC incorrectly handled certain     packet lengths. A remote attacker could possibly use this issue to obtain sensitive information, cause a     denial of service, or execute arbitrary code. (CVE-2018-15127 CVE-2018-20019, CVE-2018-20020,     CVE-2018-20021, CVE-2018-20022, CVE-2018-20023, CVE-2018-20024, CVE-2018-20748, CVE-2018-20749,     CVE-2018-20750, CVE-2018-7225, CVE-2019-15681)

Tenable has extracted the preceding description block directly from the Ubuntu security advisory.

Note that Nessus has not tested for these issues but has instead relied only on the application's self-reported version number.

The remote host is affected by the vulnerability described in GLSA-202006-06 (ssvnc: Multiple vulnerabilities)

    Multiple vulnerabilities have been discovered in ssvnc. Please review       the CVE identifiers referenced below for details.
  Impact :

    Please review the referenced CVE identifiers for details.
  Workaround :

    There is no known workaround at this time.

ID	名前	製品	ファミリー	公開日	更新日	深刻度
132345	Debian DLA-2045-1 : tightvnc security update	Nessus	Debian Local Security Checks	2019/12/23	2024/4/2	critical
121154	openSUSE Security Update : LibVNCServer (openSUSE-2019-45)	Nessus	SuSE Local Security Checks	2019/1/14	2021/1/19	critical
121158	SUSE SLED15 / SLES15 Security Update : LibVNCServer (SUSE-SU-2019:0080-1)	Nessus	SuSE Local Security Checks	2019/1/14	2021/1/13	critical
121282	openSUSE Security Update : LibVNCServer (openSUSE-2019-53)	Nessus	SuSE Local Security Checks	2019/1/22	2021/1/19	critical
121541	Ubuntu 14.04 LTS / 16.04 LTS / 18.04 LTS : LibVNCServer vulnerabilities (USN-3877-1)	Nessus	Ubuntu Local Security Checks	2019/2/1	2024/8/27	critical
222323	Linux Distros Unpatched Vulnerability : CVE-2018-20022	Nessus	Misc.	2025/3/4	2026/11/6	high
140920	Ubuntu 18.04 LTS : iTALC vulnerabilities (USN-4547-1)	Nessus	Ubuntu Local Security Checks	2020/9/28	2024/8/27	critical
137443	GLSA-202006-06 : ssvnc: Multiple vulnerabilities	Nessus	Gentoo Local Security Checks	2020/6/17	2020/6/22	critical

検出

プラグインの検索

critical

critical

critical

critical

critical

high

critical

critical