Libvncserver Project: >> Libvncserver >> 0.9.5 Security Vulnerabilities
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.
CVSS Score
8.1
EPSS Score
0.0
Published
2026-03-24
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.
CVSS Score
7.5
EPSS Score
0.018
Published
2026-03-24
It was discovered that websockets.c in LibVNCServer prior to 0.9.12 did not properly decode certain WebSocket frames. A malicious attacker could exploit this by sending specially crafted WebSocket frames to a server, causing a heap-based buffer overflow.
CVSS Score
9.8
EPSS Score
0.048
Published
2020-06-30
An issue was discovered in LibVNCServer before 0.9.13. libvncserver/scale.c has a pixel_value integer overflow.
CVSS Score
6.5
EPSS Score
0.016
Published
2020-06-17
An issue was discovered in LibVNCServer before 0.9.13. Byte-aligned data is accessed through uint32_t pointers in libvncclient/rfbproto.c. NOTE: there is reportedly "no trust boundary crossed.
CVSS Score
7.5
EPSS Score
0.025
Published
2020-06-17
An issue was discovered in LibVNCServer before 0.9.13. Byte-aligned data is accessed through uint16_t pointers in libvncserver/translate.c. NOTE: Third parties do not consider this to be a vulnerability as there is no known path of exploitation or cross of a trust boundary
CVSS Score
7.5
EPSS Score
0.025
Published
2020-06-17
A NULL pointer dereference flaw was found in the way LibVNCServer before 0.9.9 handled certain ClientCutText message. A remote attacker could use this flaw to crash the VNC server by sending a specially crafted ClientCutText message from a VNC client.
CVSS Score
7.5
EPSS Score
0.034
Published
2020-02-05
An issue was discovered in LibVNCServer through 0.9.11. rfbProcessClientNormalMessage() in rfbserver.c does not sanitize msg.cct.length, leading to access to uninitialized and potentially sensitive data or possibly unspecified other impact (e.g., an integer overflow) via specially crafted VNC packets.
CVSS Score
9.8
EPSS Score
0.043
Published
2018-02-19
Heap-based buffer overflow in rfbproto.c in LibVNCClient in LibVNCServer before 0.9.11 allows remote servers to cause a denial of service (application crash) or possibly execute arbitrary code via a crafted FramebufferUpdate message containing a subrectangle outside of the client drawing area.
CVSS Score
9.8
EPSS Score
0.008
Published
2016-12-31