{
  "affected": [
    {
      "ranges": [
        {
          "database_specific": {
            "extracted_events": [
              {
                "introduced": "0"
              },
              {
                "last_affected": "0.9.15"
              }
            ],
            "source": [
              "AFFECTED_FIELD",
              "REFERENCES"
            ]
          },
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "5b270544b85233668b98161323297d418a8f5fd1"
            }
          ],
          "repo": "https://github.com/libvnc/libvncserver",
          "type": "GIT"
        }
      ]
    }
  ],
  "aliases": [
    "GHSA-jcc5-8wj4-7c58"
  ],
  "database_specific": {
    "cna_assigner": "GitHub_M",
    "cwe_ids": [
      "CWE-787"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44988.json"
  },
  "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.",
  "id": "CVE-2026-44988",
  "modified": "2026-07-15T01:48:56.816810749Z",
  "published": "2026-05-27T14:26:50.063Z",
  "references": [
    {
      "type": "ADVISORY",
      "url": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/44xxx/CVE-2026-44988.json"
    },
    {
      "type": "ADVISORY",
      "url": "https://github.com/LibVNC/libvncserver/security/advisories/GHSA-jcc5-8wj4-7c58"
    },
    {
      "type": "ADVISORY",
      "url": "https://nvd.nist.gov/vuln/detail/CVE-2026-44988"
    },
    {
      "type": "FIX",
      "url": "https://github.com/LibVNC/libvncserver/commit/5b270544b85233668b98161323297d418a8f5fd1"
    }
  ],
  "schema_version": "1.8.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H",
      "type": "CVSS_V3"
    }
  ],
  "summary": "LibVNCClient Tight Gradient decoding allows malicious server-triggered heap/stack OOB writes"
}