CVE-2026-32854
CVE-2026-32854 is a high-severity vulnerability in Libvncserver Project Libvncserver with a CVSS 3.x base score of 7.5. 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-476.
Key facts
- Severity: High (CVSS 3.x base score 7.5)
- CVSS v4: 6.3
- EPSS exploit prediction: 5% (92nd percentile)
- Actively exploited: Not listed in CISA KEV
- EU (EUVD) id: EUVD-2026-14932
- Weakness: CWE-476
- Affected product: Libvncserver Project Libvncserver
- Published:
- Last modified:
Description
LibVNCServer versions 0.9.15 and prior (fixed in commit dc78dee) contain null pointer dereference vulnerabilities in the HTTP proxy handlers within httpProcessInput() in httpd.c that allow remote attackers to cause a denial of service by sending specially crafted HTTP requests. Attackers can exploit missing validation of strchr() return values in the CONNECT and GET proxy handling paths to trigger null pointer dereferences and crash the server when httpd and proxy features are enabled.
Frequently asked questions
- What is CVE-2026-32854?
- LibVNCServer versions 0.9.15 and prior (fixed in commit dc78dee) contain null pointer dereference vulnerabilities in the HTTP proxy handlers within httpProcessInput() in httpd.c that allow remote attackers to cause a denial of service by sending specially crafted HTTP requests. Attackers can exploit missing validation of strchr() return values in the CONNECT and GET proxy handling paths to trigger null pointer dereferences and crash the server when httpd and proxy features are enabled.
- How severe is CVE-2026-32854?
- CVE-2026-32854 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
- Is CVE-2026-32854 being actively exploited?
- It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (92nd percentile), an estimate of the probability of exploitation in the next 30 days.
- What products are affected by CVE-2026-32854?
- CVE-2026-32854 affects Libvncserver Project Libvncserver. See the affected-products list for the exact vulnerable versions.
- How do I fix CVE-2026-32854?
- 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-2026-32854 have an EU (EUVD) identifier?
- Yes. CVE-2026-32854 is tracked in the ENISA EU Vulnerability Database (EUVD) as EUVD-2026-14932.
- When was CVE-2026-32854 published?
- CVE-2026-32854 was published on 2026-03-24 and last updated on 2026-06-17.
References
- https://github.com/LibVNC/libvncserver/commit/dc78dee51a7e270e537a541a17befdf2073f5314
- https://github.com/LibVNC/libvncserver/security/advisories/GHSA-xjp8-4qqv-5x4x
- https://www.vulncheck.com/advisories/libvncserver-httpd-proxy-null-pointer-dereference
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-2026-32853 — High (CVSS 8.1): LibVNCServer versions 0.9.15 and prior (fixed in commit 009008e) contain a heap out-of-bounds read vulnerability 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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