Libvncserver
CVE-2018-20020
CRITICAL
Severity by source
AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Primary rating from NVD · only source for this CVE.
CVSS VectorNVD
CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Lifecycle Timeline
1DescriptionNVD
LibVNC before commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4d contains heap out-of-bound write vulnerability inside structure in VNC client code that can result remote code execution
AnalysisAI
LibVNC before commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4d contains heap out-of-bound write vulnerability inside structure in VNC client code that can result remote code execution. Rated critical severity (CVSS 9.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity. No vendor patch available.
Technical ContextAI
This vulnerability is classified as Out-of-bounds Write (CWE-787), which allows attackers to write data beyond allocated buffer boundaries leading to code execution or crashes. LibVNC before commit 7b1ef0ffc4815cab9a96c7278394152bdc89dc4d contains heap out-of-bound write vulnerability inside structure in VNC client code that can result remote code execution Affected products include: Libvnc Project Libvncserver, Canonical Ubuntu Linux, Debian Debian Linux.
RemediationAI
No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Validate write boundaries, use memory-safe languages, enable compiler protections (ASLR, stack canaries).
More in Libvncserver
View allAn issue was discovered in LibVNCServer through 0.9.11. Rated critical severity (CVSS 9.8), this vulnerability is remote
The HandleRFBServerMessage function in libvncclient/rfbproto.c in LibVNCServer 0.9.9 and earlier does not check certain
The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer 0.9.9 and earlier does not proper
A divide by zero issue was found to occur in libvncserver-0.9.12. Rated high severity (CVSS 7.5), this vulnerability is
The rfbProcessClientNormalMessage function in libvncserver/rfbserver.c in LibVNCServer 0.9.9 and earlier allows remote a
Heap-based buffer overflow in ultra.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a den
Heap-based buffer overflow in rfbproto.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a
LibVNC before commit a83439b9fbe0f03c48eb94ed05729cb016f8b72f contains multiple heap out-of-bound write vulnerabilities
LibVNC before commit 502821828ed00b4a2c4bef90683d0fd88ce495de contains heap out-of-bound write vulnerability in server c
LibVNC before commit 73cb96fec028a576a5a24417b57723b55854ad7b contains heap use-after-free vulnerability in server code
Integer overflow in the MallocFrameBuffer function in vncviewer.c in LibVNCServer 0.9.9 and earlier allows remote VNC se
Multiple stack-based buffer overflows in the File Transfer feature in rfbserver.c in LibVNCServer 0.9.9 and earlier allo
Same weakness CWE-787 – Out-of-bounds Write
View allSame technique Memory Corruption
View allShare
External POC / Exploit Code
Leaving vuln.today