{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-50256", "assignerOrgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "state": "PUBLISHED", "assignerShortName": "redhat", "dateReserved": "2026-06-04T14:55:24.011Z", "datePublished": "2026-06-05T10:31:22.122Z", "dateUpdated": "2026-06-05T10:31:22.122Z"}, "containers": {"cna": {"title": "Xorg-x11-server: xorg-x11-server-xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libxfont2 name length mismatch", "metrics": [{"other": {"content": {"value": "Important", "namespace": "https://access.redhat.com/security/updates/classification/"}, "type": "Red Hat severity rating"}}, {"cvssV3_1": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "format": "CVSS"}], "descriptions": [{"lang": "en", "value": "A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root."}], "affected": [{"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 10", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "xorg-x11-server-Xwayland", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:10"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 6", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "xorg-x11-server", "defaultStatus": "unknown", "cpes": ["cpe:/o:redhat:enterprise_linux:6"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 7", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "xorg-x11-server", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:7"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "xorg-x11-server", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:8"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 8", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "xorg-x11-server-Xwayland", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:8"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "xorg-x11-server", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:9"]}, {"vendor": "Red Hat", "product": "Red Hat Enterprise Linux 9", "collectionURL": "https://access.redhat.com/downloads/content/package-browser/", "packageName": "xorg-x11-server-Xwayland", "defaultStatus": "affected", "cpes": ["cpe:/o:redhat:enterprise_linux:9"]}], "references": [{"url": "https://access.redhat.com/security/cve/CVE-2026-50256", "tags": ["vdb-entry", "x_refsource_REDHAT"]}, {"url": "https://bugzilla.redhat.com/show_bug.cgi?id=2485380", "name": "RHBZ#2485380", "tags": ["issue-tracking", "x_refsource_REDHAT"]}, {"url": "https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07"}, {"url": "https://lists.x.org/archives/xorg-announce/2026-June/003702.html"}, {"url": "https://redhat.atlassian.net/browse/PSIRTSUPT-16950"}], "datePublic": "2026-06-02T00:00:00.000Z", "problemTypes": [{"descriptions": [{"cweId": "CWE-121", "description": "Stack-based Buffer Overflow", "lang": "en", "type": "CWE"}]}], "x_redhatCweChain": "CWE-121: Stack-based Buffer Overflow", "timeline": [{"lang": "en", "time": "2026-05-15T03:14:46.000Z", "value": "Reported to Red Hat."}, {"lang": "en", "time": "2026-06-02T00:00:00.000Z", "value": "Made public."}], "credits": [{"lang": "en", "value": "Upstream acknowledges Anonymous (Trend Micro Zero Day Initiative) as the original reporter."}], "providerMetadata": {"orgId": "53f830b8-0a3f-465b-8143-3b8a9948e749", "shortName": "redhat", "dateUpdated": "2026-06-05T10:31:22.122Z"}, "x_generator": {"engine": "cvelib 1.8.0"}}}}

{}

{"cveTags": [], "descriptions": [{"lang": "en", "value": "A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root."}], "id": "CVE-2026-50256", "lastModified": "2026-06-05T13:27:38.750", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "LOW", "attackVector": "LOCAL", "availabilityImpact": "HIGH", "baseScore": 7.8, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "LOW", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.8, "impactScore": 5.9, "source": "secalert@redhat.com", "type": "Primary"}]}, "published": "2026-06-05T12:16:38.727", "references": [{"source": "secalert@redhat.com", "url": "https://access.redhat.com/security/cve/CVE-2026-50256"}, {"source": "secalert@redhat.com", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2485380"}, {"source": "secalert@redhat.com", "url": "https://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07"}, {"source": "secalert@redhat.com", "url": "https://lists.x.org/archives/xorg-announce/2026-June/003702.html"}, {"source": "secalert@redhat.com", "url": "https://redhat.atlassian.net/browse/PSIRTSUPT-16950"}], "sourceIdentifier": "secalert@redhat.com", "vulnStatus": "Undergoing Analysis", "weaknesses": [{"description": [{"lang": "en", "value": "CWE-121"}], "source": "secalert@redhat.com", "type": "Primary"}]}

{"acknowledgement": "Upstream acknowledges Anonymous (Trend Micro Zero Day Initiative) as the original reporter.", "bugzilla": {"description": "xorg-x11-server: xorg-x11-server-Xwayland: xorg-x11-server: stack buffer overflow in font alias resolution due to libXfont2 name length mismatch", "id": "2485380", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2485380"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.8", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-121", "details": ["A stack-based buffer overflow flaw was found in the X.Org X server and Xwayland. A mismatch between the X server and the libXfont2 library's maximum font name length can cause a stack buffer overflow during font alias resolution. The server allocates a 256 byte stack buffer but libXfont2's alias target name length is 1024 bytes. A font alias name between 257 and 1023 bytes causes the X server to copy that name into the undersized stack buffer without further checks. This may be used to crash the server, or for privilege escalation if the X server runs as root."], "name": "CVE-2026-50256", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "impact": "important", "package_name": "xorg-x11-server-Xwayland", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Out of support scope", "impact": "important", "package_name": "xorg-x11-server", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Affected", "impact": "important", "package_name": "xorg-x11-server", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "impact": "important", "package_name": "xorg-x11-server", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "impact": "important", "package_name": "xorg-x11-server-Xwayland", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "impact": "important", "package_name": "xorg-x11-server", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "impact": "important", "package_name": "xorg-x11-server-Xwayland", "product_name": "Red Hat Enterprise Linux 9"}], "public_date": "2026-06-02T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-50256\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-50256\nhttps://gitlab.freedesktop.org/xorg/xserver/-/commit/bb5158f962dc935e58ef8b4b5fcb31be201a6e07\nhttps://lists.x.org/archives/xorg-announce/2026-June/003702.html\nhttps://redhat.atlassian.net/browse/PSIRTSUPT-16950"], "threat_severity": "Important"}

{"created": "2026-06-05T12:30:40.753840+00:00", "updated": "2026-06-05T12:30:40.754073+00:00", "vendors": []}