How severe is CVE-2019-15691?

CVE-2019-15691 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2019-15691 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2019-15691?

CVE-2019-15691 primarily affects Tigervnc. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2019-15691?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.

When was CVE-2019-15691 published?

CVE-2019-15691 was published on 2019-12-26 and last updated on 2026-06-17.

CVE-2019-15691

CVE-2019-15691 is a high-severity vulnerability in Tigervnc with a CVSS 3.x base score of 7.2. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-672.

Key facts

Severity: High (CVSS 3.x base score 7.2)
CVSS v2: 6.5
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-672
Affected product: Tigervnc
Published: 2019-12-26
Last modified: 2026-06-17

Description

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.

Frequently asked questions

What is CVE-2019-15691?: 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.
How severe is CVE-2019-15691?: CVE-2019-15691 has a CVSS 3.x base score of 7.2, rated high severity. It is exploitable over network with low attack complexity, requires high privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2019-15691 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2019-15691?: CVE-2019-15691 primarily affects Tigervnc. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2019-15691?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2019-15691 published?: CVE-2019-15691 was published on 2019-12-26 and last updated on 2026-06-17.

References

Affected products (2)

cpe:2.3:a:tigervnc:tigervnc:*:*:*:*:*:*:*:*
cpe:2.3:o:opensuse:leap:15.1:*:*:*:*:*:*:*

More vulnerabilities in Tigervnc

CVE-2014-0011 — Critical (CVSS 9.8): Multiple heap-based buffer overflows in the ZRLE_DECODE function in common/rfb/zrleDecode.h in TigerVNC before 1.3.1,…
CVE-2017-5581 — Critical (CVSS 9.8): Buffer overflow in the ModifiablePixelBuffer::fillRect function in TigerVNC before 1.7.1 allows remote servers to…
CVE-2014-8241 — Critical (CVSS 9.8): XRegion in TigerVNC allows remote VNC servers to cause a denial of service (NULL pointer dereference) by leveraging…
CVE-2017-7393 — High (CVSS 8.8): In TigerVNC 1.7.1 (VNCSConnectionST.cxx VNCSConnectionST::fence), an authenticated client can cause a double free,…
CVE-2026-34352 — High (CVSS 8.5): In TigerVNC before 1.16.2, Image.cxx in x0vncserver allows other users to observe or manipulate the screen contents, or…
CVE-2020-26117 — High (CVSS 8.1): In rfb/CSecurityTLS.cxx and rfb/CSecurityTLS.java in TigerVNC before 1.11.0, viewers mishandle TLS certificate…

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