NetSurf libnsbmp through 0.1.7 Out-of-Bounds Read via bmp_decode_mask

{
  "id": "ec6fa6705154ecc8570f985993d8c3f003b09a3cfe921854d3f3e944f5f73756",
  "url": "https://www.cve.org/CVERecord?id=CVE-2026-111139",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "NetSurf libnsbmp through 0.1.7 Out-of-Bounds Read via bmp_decode_mask",
    "summary": "NetSurf libnsbmp through 0.1.7 contains an out-of-bounds read vulnerability in bmp_decode_mask() that allows attackers to read one byte past the image buffer by supplying crafted ICO files. Attackers can provide an ICO whose inner bitmap width is not a multiple of 8, causing a heap over-read that can crash applications calling bmp_decode().",
    "evidence": "cve:CVE-2026-111139",
    "products": [
      {
        "name": {
          "value": "libnsbmp",
          "evidence": "/containers/cna/affected/0/product"
        },
        "prerequisites": [],
        "fixed_versions": [],
        "affected_versions": []
      }
    ],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-111139",
      "aliases": [
        "CVE-2026-111139"
      ],
      "metrics": [
        {
          "format": "CVSS",
          "cvssV4_0": {
            "version": "4.0",
            "baseScore": 6.8,
            "attackVector": "LOCAL",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:4.0/AV:L/AC:L/AT:N/PR:N/UI:P/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N",
            "userInteraction": "PASSIVE",
            "attackComplexity": "LOW",
            "attackRequirements": "NONE",
            "privilegesRequired": "NONE",
            "subIntegrityImpact": "NONE",
            "vulnIntegrityImpact": "NONE",
            "subAvailabilityImpact": "NONE",
            "vulnAvailabilityImpact": "HIGH",
            "subConfidentialityImpact": "NONE",
            "vulnConfidentialityImpact": "NONE"
          }
        },
        {
          "format": "CVSS",
          "cvssV3_1": {
            "scope": "UNCHANGED",
            "version": "3.1",
            "baseScore": 5.5,
            "attackVector": "LOCAL",
            "baseSeverity": "MEDIUM",
            "vectorString": "CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H",
            "integrityImpact": "NONE",
            "userInteraction": "REQUIRED",
            "attackComplexity": "LOW",
            "availabilityImpact": "HIGH",
            "privilegesRequired": "NONE",
            "confidentialityImpact": "NONE"
          }
        }
      ],
      "affected": [
        {
          "repo": "https://github.com/netsurf-browser/libnsbmp",
          "vendor": "NetSurf",
          "product": "libnsbmp",
          "versions": [
            {
              "status": "affected",
              "version": "0",
              "versionType": "custom",
              "lessThanOrEqual": "0.1.7"
            }
          ],
          "packageURL": "pkg:github/netsurf-browser/libnsbmp",
          "collectionURL": "https://github.com/netsurf-browser/libnsbmp",
          "defaultStatus": "unaffected"
        }
      ],
      "modified": "2026-10-26T14:04:23.877Z",
      "provider": "cve",
      "references": [
        "https://hackmd.io/@haind-pwn/libnsbmp-rle-absolute-pad-and-ico-mask-oob-read",
        "https://github.com/netsurf-browser/libnsbmp/blob/ea063c9f46acb43e90208da14073332b505ef7e7/src/libnsbmp.c#L835-L873",
        "https://download.netsurf-browser.org/libs/releases/libnsbmp-0.1.7-src.tar.gz",
        "https://github.com/netsurf-browser/libnsbmp",
        "https://www.vulncheck.com/advisories/netsurf-libnsbmp-through-0.1.7-out-of-bounds-read-via-bmp-decode-mask"
      ],
      "provider_metadata": {
        "adp": [
          {
            "title": "CISA ADP Vulnrichment",
            "metrics": [
              {
                "other": {
                  "type": "ssvc",
                  "content": {
                    "id": "CVE-2026-111139",
                    "role": "CISA Coordinator",
                    "options": [
                      {
                        "Exploitation": "poc"
                      },
                      {
                        "Automatable": "no"
                      },
                      {
                        "Technical Impact": "partial"
                      }
                    ],
                    "version": "2.0.3",
                    "timestamp": "2026-10-26T14:04:11.655695Z"
                  }
                }
              }
            ],
            "providerMetadata": {
              "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
              "shortName": "CISA-ADP",
              "dateUpdated": "2026-10-26T14:04:23.877Z"
            }
          }
        ],
        "cna": {
          "orgId": "83251b91-4cc7-4094-a5c7-464a1b83ea10",
          "shortName": "VulnCheck",
          "dateUpdated": "2026-10-15T18:57:31.959Z"
        }
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-111139",
        "evidence": "/cveMetadata/cveId"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/containers/cna/metrics"
  },
  "source_id": "core-cve",
  "document_id": 311554,
  "published_at": "2026-10-15T18:57:31.959+00:00"
}