How severe is CVE-2026-32853?

CVE-2026-32853 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability high.

Is CVE-2026-32853 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2026-32853?

CVE-2026-32853 affects Libvncserver Project Libvncserver. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2026-32853?

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.

Does CVE-2026-32853 have an EU (EUVD) identifier?

Yes. CVE-2026-32853 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14930.

When was CVE-2026-32853 published?

CVE-2026-32853 was published on 2026-03-24 and last updated on 2026-06-17.

CVE-2026-32853

CVE-2026-32853 is a high-severity vulnerability in Libvncserver Project Libvncserver with a CVSS 3.x base score of 8.1. 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-125.

Key facts

Severity: High (CVSS 3.x base score 8.1)
CVSS v4: 6.9
EPSS exploit prediction: 0% (35th percentile)
Actively exploited: Not listed in CISA KEV
EU (EUVD) id: EUVD-2026-14930
Weakness: CWE-125
Affected product: Libvncserver Project Libvncserver
Published: 2026-03-24
Last modified: 2026-06-17

Description

LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler that allows a malicious VNC server to cause information disclosure or application crash. Attackers can exploit improper bounds checking in the HandleUltraZipBPP() function by manipulating subrectangle header counts to read beyond the allocated heap buffer.

Frequently asked questions

What is CVE-2026-32853?: LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability in the UltraZip encoding handler that allows a malicious VNC server to cause information disclosure or application crash. Attackers can exploit improper bounds checking in the HandleUltraZipBPP() function by manipulating subrectangle header counts to read beyond the allocated heap buffer.
How severe is CVE-2026-32853?: CVE-2026-32853 has a CVSS 3.x base score of 8.1, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is high, integrity none, and availability high.
Is CVE-2026-32853 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 0% (35th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2026-32853?: CVE-2026-32853 affects Libvncserver Project Libvncserver. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2026-32853?: 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.
Does CVE-2026-32853 have an EU (EUVD) identifier?: Yes. CVE-2026-32853 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14930.
When was CVE-2026-32853 published?: CVE-2026-32853 was published on 2026-03-24 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:libvncserver_project:libvncserver:*:*:*:*:*:*:*:*

More vulnerabilities in Libvncserver Project Libvncserver

CVE-2017-18922 — Critical (CVSS 9.8): It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames. A…
CVE-2018-7225 — Critical (CVSS 9.8): An issue was discovered in LibVNCServer through 0.9.11. rfbProcessClientNormalMessage() in rfbserver.c does not…
CVE-2016-9942 — Critical (CVSS 9.8): Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a…
CVE-2016-9941 — Critical (CVSS 9.8): Heap-based buffer overflow in rfbproto.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a…
CVE-2026-32854 — High (CVSS 7.5): LibVNCServer versions 0.9.15 and prior (fixed in commit dc78dee) contain null pointer dereference vulnerabilities in…
CVE-2020-29260 — High (CVSS 7.5): libvncclient v0.9.13 was discovered to contain a memory leak via the function rfbClientCleanup().

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Other CWE-125 (Out-of-bounds Read) vulnerabilities

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