ALAS2-2020-1552


Amazon Linux 2 Security Advisory: ALAS-2020-1552
Advisory Release Date: 2020-10-22 18:47 Pacific
Advisory Updated Date: 2020-10-22 22:33 Pacific
Severity: Low

Issue Overview:

TigerVNC version prior to 1.10.1 is vulnerable to stack use-after-return, which occurs 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. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15691)

TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow. Vulnerability could be triggered from CopyRectDecoder due to incorrect value checks. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15692)

TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow, which occurs in TightDecoder::FilterGradient. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15693)

TigerVNC version prior to 1.10.1 is vulnerable to heap buffer overflow, which could be triggered from DecodeManager::decodeRect. Vulnerability occurs due to the signdness error in processing MemOutStream. Exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15694)

TigerVNC version prior to 1.10.1 is vulnerable to stack buffer overflow, which could be triggered from CMsgReader::readSetCursor. This vulnerability occurs due to insufficient sanitization of PixelFormat. Since remote attacker can choose offset from start of the buffer to start writing his values, exploitation of this vulnerability could potentially result into remote code execution. This attack appear to be exploitable via network connectivity. (CVE-2019-15695)


Affected Packages:

tigervnc


Issue Correction:
Run yum update tigervnc to update your system.

New Packages:
aarch64:
    tigervnc-1.8.0-21.amzn2.aarch64
    tigervnc-server-1.8.0-21.amzn2.aarch64
    tigervnc-server-minimal-1.8.0-21.amzn2.aarch64
    tigervnc-server-module-1.8.0-21.amzn2.aarch64
    tigervnc-debuginfo-1.8.0-21.amzn2.aarch64

i686:
    tigervnc-1.8.0-21.amzn2.i686
    tigervnc-server-1.8.0-21.amzn2.i686
    tigervnc-server-minimal-1.8.0-21.amzn2.i686
    tigervnc-server-module-1.8.0-21.amzn2.i686
    tigervnc-debuginfo-1.8.0-21.amzn2.i686

noarch:
    tigervnc-server-applet-1.8.0-21.amzn2.noarch
    tigervnc-license-1.8.0-21.amzn2.noarch
    tigervnc-icons-1.8.0-21.amzn2.noarch

src:
    tigervnc-1.8.0-21.amzn2.src

x86_64:
    tigervnc-1.8.0-21.amzn2.x86_64
    tigervnc-server-1.8.0-21.amzn2.x86_64
    tigervnc-server-minimal-1.8.0-21.amzn2.x86_64
    tigervnc-server-module-1.8.0-21.amzn2.x86_64
    tigervnc-debuginfo-1.8.0-21.amzn2.x86_64