CVE-2026-44988

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Source
https://cve.org/CVERecord?id=CVE-2026-44988
Import Source
https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44988.json
JSON Data
https://api.osv.dev/v1/vulns/CVE-2026-44988
Aliases
  • GHSA-jcc5-8wj4-7c58
Downstream
Related
Published
2026-05-27T14:26:50.063Z
Modified
2026-08-04T11:50:32.072612267Z
Severity
  • 8.8 (High) CVSS_V3 - CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H CVSS Calculator
Summary
LibVNCClient Tight Gradient decoding allows malicious server-triggered heap/stack OOB writes
Details

LibVNCClient is a library for easy implementation of a VNC client. In 0.9.15 and earlier, LibVNCClient's Tight encoding decoder uses fixed-size 2048-pixel scratch buffers for the Gradient filter, but it does not reject Tight rectangles whose width is larger than 2048 pixels. A malicious VNC server can send a crafted FramebufferUpdate rectangle using Tight encoding with NoZlib | ExplicitFilter and the Gradient filter. When a LibVNCClient-based client connects, the client processes the server-controlled rectangle width and writes beyond fixed-size Gradient buffers. This vulnerability is fixed with commit 5b270544b85233668b98161323297d418a8f5fd1.

Database specific 
{
    "cwe_ids": [
        "CWE-787"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44988.json",
    "cna_assigner": "GitHub_M"
}
References

Affected packages

Git / github.com/libvnc/libvncserver

Affected ranges

Type
GIT
Repo
https://github.com/libvnc/libvncserver
Events
Introduced
0 Unknown introduced commit / All previous commits are affected
Last affected
9b54b1ec32731bd23158ca014dc18014db4194c3
Database specific 
{
    "extracted_events": [
        {
            "introduced": "0"
        },
        {
            "last_affected": "0.9.15"
        }
    ],
    "source": "AFFECTED_FIELD"
}

Affected versions

LibVNCServer-0.*
LibVNCServer-0.9.10
LibVNCServer-0.9.11
LibVNCServer-0.9.12
LibVNCServer-0.9.13
LibVNCServer-0.9.14
LibVNCServer-0.9.15
LibVNCServer-0.9.8
LibVNCServer-0.9.9
Other
X11VNC_0_9_10
X11VNC_0_9_11
X11VNC_0_9_12
X11VNC_0_9_7
X11VNC_0_9_8
X11VNC_0_9_9
X11VNC_REL_0_9_4
X11VNC_REL_0_9_5
X11VNC_REL_0_9_6

Database specific

source 
"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-44988.json"