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Fencer Vulns
high 7.2

CVE-2019-15691 json

TigerVNC version prior to 1.10.1 is vulnerable to stack use-after-return, which occurs due to incorrect usage of stack memory in ZRLEDecode…

published 2019-12-26 6 y ago modified 2026-06-17 4 mo ago also EUVD-2019-6630

cvss
7.2
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
4.7%
EPSS 4.7% chance of exploitation in 30 days, percentile 91%
public exploits
0
none known

Summary

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.

Patch / fix

  • tigervnc tigervnc 1.10.1
  • tigervnc Debian 14, Debian 13, Debian 12 1.10.1+dfsg-1

debian advisories DEBIAN-CVE-2019-15691

  • tigervnc RHEL 7 1.8.0-21.el7
  • tigervnc-icons RHEL 7 1.8.0-21.el7
  • tigervnc-server RHEL 7 1.8.0-21.el7
  • tigervnc-license RHEL 7 1.8.0-21.el7
  • tigervnc-server-applet RHEL 7 1.8.0-21.el7
  • tigervnc-server-module RHEL 7 1.8.0-21.el7
  • tigervnc-server-minimal RHEL 7 1.8.0-21.el7
  • tigervnc RHEL 8 1.9.0-14.el8_1

red hat advisories RHSA-2020:3875RHSA-2020:1497

  • tigervnc SLES for SAP 12 SP5, SLES for SAP 12 SP4, SLES 12 SP5 +1 more 1.6.0-22.14.1
  • tigervnc SLES for SAP 12 SP3, SLES for SAP 12 SP2, SLES 12 SP3-LTSS +8 more 1.6.0-18.28.1
  • tigervnc SLE Module for Desktop Applications 15 SP1, SLE Module for Basesystem 15 SP1 1.9.0-19.3.1
  • tigervnc SLE Module for Desktop Applications 15, SLE Module for Basesystem 15 1.8.0-13.11.1
  • tigervnc SLES for SAP 12 SP1, SLES 12 SP1-LTSS 1.4.3-25.11.1

suse advisories SUSE-SU-2020:1749-1SUSE-SU-2020:0266-1SUSE-SU-2020:0159-1SUSE-SU-2020:0113-1SUSE-SU-2020:0112-1

  • tigervnc openSUSE Tumbleweed 1.10.1-17.1
  • tigervnc openSUSE Leap 15.1 1.9.0-lp151.4.3.1

opensuse advisories openSUSE-SU-2024:10591-1openSUSE-SU-2020:0087-1

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2019-15691 updated cvss 7.2

tigervnc: Stack use-after-return due to incorrect usage of stack memory in ZRLEDecoder

  • Red Hat Enterprise Linux 6 tigervnc, tigervnc-server, tigervnc-server-applet, tigervnc-server-module
    affected: no fix planned “Out of support scope”
  • Red Hat Enterprise Linux AppStream (v. 8) tigervnc 1.9.0-14.el8_1, tigervnc-icons 1.9.0-14.el8_1, tigervnc-server 1.9.0-14.el8_1, tigervnc-license 1.9.0-14.el8_1, tigervnc-server-applet 1.9.0-14.el8_1, tigervnc-server-module 1.9.0-14.el8_1, +1 more
    fixed: vendor fix RHSA-2020:1497
  • Red Hat Enterprise Linux Client (v. 7) tigervnc 1.8.0-21.el7, tigervnc-icons 1.8.0-21.el7, tigervnc-server 1.8.0-21.el7, tigervnc-license 1.8.0-21.el7, tigervnc-server-minimal 1.8.0-21.el7 Red Hat Enterprise Linux Client Optional (v. 7) tigervnc-server-applet 1.8.0-21.el7, tigervnc-server-module 1.8.0-21.el7 Red Hat Enterprise Linux ComputeNode (v. 7) tigervnc 1.8.0-21.el7, tigervnc-license 1.8.0-21.el7, tigervnc-server-minimal 1.8.0-21.el7 Red Hat Enterprise Linux ComputeNode Optional (v. 7) tigervnc 1.8.0-21.el7, tigervnc-icons 1.8.0-21.el7, tigervnc-server 1.8.0-21.el7, tigervnc-server-applet 1.8.0-21.el7, tigervnc-server-module 1.8.0-21.el7 Red Hat Enterprise Linux Server (v. 7) tigervnc 1.8.0-21.el7, tigervnc-icons 1.8.0-21.el7, tigervnc-server 1.8.0-21.el7, tigervnc-license 1.8.0-21.el7, tigervnc-server-minimal 1.8.0-21.el7 Red Hat Enterprise Linux Server Optional (v. 7) tigervnc-server-applet 1.8.0-21.el7, tigervnc-server-module 1.8.0-21.el7
    +2 more products
    Red Hat Enterprise Linux Workstation (v. 7) tigervnc 1.8.0-21.el7, tigervnc-icons 1.8.0-21.el7, tigervnc-server 1.8.0-21.el7, tigervnc-license 1.8.0-21.el7, tigervnc-server-minimal 1.8.0-21.el7 Red Hat Enterprise Linux Workstation Optional (v. 7) tigervnc-server-applet 1.8.0-21.el7, tigervnc-server-module 1.8.0-21.el7
    fixed: vendor fix RHSA-2020:3875

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

Exploit prediction

4.72% chance of exploitation in the next 30 days, higher than 91% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • openwall.com https://www.openwall.com/lists/oss-security/2019/12/20/2 referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
NVD 3.1 7.2 CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:H/I:H/A:H
NVD 2.0 6.5 AV:N/AC:L/Au:S/C:P/I:P/A:P

Affected products

  • Kaspersky TigerVNC

Classification

Weakness
  • CWE-825 Expired Pointer Dereference
  • CWE-672 Operation on a Resource after Expiration or Release

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.