{"id":"USN-8913-1","summary":"libx11 vulnerabilities","details":"Adam Bedard discovered that libx11 incorrectly handled certain XKB keyboard\nmap replies. If a user were tricked into connecting to a malicious X\nserver, a remote attacker could possibly use this issue to cause libx11 to\ncrash, resulting in a denial of service, or possibly execute arbitrary\ncode. (CVE-2026-88806)\n\nIt was discovered that libx11 incorrectly handled certain X Input Method\n(XIM) messages. If a user were tricked into connecting to a malicious X\nserver, a remote attacker could possibly use these issues to cause libx11\nto crash, resulting in a denial of service. (CVE-2026-94283,\nCVE-2026-94284)\n\nIt was discovered that libx11 incorrectly handled converting certain\nmultibyte text. An attacker could possibly use this issue to cause libx11\nto crash, resulting in a denial of service. (CVE-2026-94285)","modified":"2026-10-12T20:28:09.464073800Z","published":"2026-10-12T12:53:41Z","related":["UBUNTU-CVE-2026-88806","UBUNTU-CVE-2026-94283","UBUNTU-CVE-2026-94284","UBUNTU-CVE-2026-94285"],"upstream":["CVE-2026-88806","CVE-2026-94283","CVE-2026-94284","CVE-2026-94285","UBUNTU-CVE-2026-88806","UBUNTU-CVE-2026-94283","UBUNTU-CVE-2026-94284","UBUNTU-CVE-2026-94285"],"references":[{"type":"ADVISORY","url":"https://ubuntu.com/security/notices/USN-8913-1"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-88806"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-94283"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-94284"},{"type":"REPORT","url":"https://ubuntu.com/security/CVE-2026-94285"}],"affected":[{"package":{"name":"libx11","ecosystem":"Ubuntu:Pro:14.04:LTS","purl":"pkg:deb/ubuntu/libx11?arch=source&distro=esm-infra-legacy%2Ftrusty"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:1.6.2-1ubuntu2.1+esm6"}]}],"versions":["2:1.6.1-1ubuntu1","2:1.6.1-1ubuntu2","2:1.6.2-1ubuntu1","2:1.6.2-1ubuntu2","2:1.6.2-1ubuntu2.1","2:1.6.2-1ubuntu2.1+esm1","2:1.6.2-1ubuntu2.1+esm2","2:1.6.2-1ubuntu2.1+esm3","2:1.6.2-1ubuntu2.1+esm4","2:1.6.2-1ubuntu2.1+esm5"],"ecosystem_specific":{"binaries":[{"binary_name":"libx11-6","binary_version":"2:1.6.2-1ubuntu2.1+esm6"},{"binary_name":"libx11-data","binary_version":"2:1.6.2-1ubuntu2.1+esm6"},{"binary_name":"libx11-xcb1","binary_version":"2:1.6.2-1ubuntu2.1+esm6"}],"availability":"Available with Ubuntu Pro with Legacy support add-on: https://ubuntu.com/pro"},"database_specific":{"cves_map":{"cves":[{"id":"CVE-2026-88806","severity":[{"score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","type":"CVSS_V3"},{"score":"medium","type":"Ubuntu"}]},{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-94283"},{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-94284"},{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-94285"}],"ecosystem":"Ubuntu:Pro:14.04:LTS"},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8913-1.json"}},{"package":{"name":"libx11","ecosystem":"Ubuntu:Pro:16.04:LTS","purl":"pkg:deb/ubuntu/libx11?arch=source&distro=esm-infra-legacy%2Fxenial"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:1.6.3-1ubuntu2.2+esm5"}]}],"versions":["2:1.6.3-1ubuntu2","2:1.6.3-1ubuntu2.1","2:1.6.3-1ubuntu2.2","2:1.6.3-1ubuntu2.2+esm1","2:1.6.3-1ubuntu2.2+esm2","2:1.6.3-1ubuntu2.2+esm3","2:1.6.3-1ubuntu2.2+esm4"],"ecosystem_specific":{"availability":"Available 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https://ubuntu.com/pro","binaries":[{"binary_name":"libx11-6","binary_version":"2:1.6.3-1ubuntu2.2+esm5"},{"binary_version":"2:1.6.3-1ubuntu2.2+esm5","binary_name":"libx11-data"},{"binary_name":"libx11-xcb1","binary_version":"2:1.6.3-1ubuntu2.2+esm5"}]},"database_specific":{"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8913-1.json","cves_map":{"ecosystem":"Ubuntu:Pro:16.04:LTS","cves":[{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-88806"},{"id":"CVE-2026-94283","severity":[{"score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}]},{"severity":[{"score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-94284"},{"id":"CVE-2026-94285","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L"},{"type":"Ubuntu","score":"medium"}]}]}}},{"package":{"name":"libx11","ecosystem":"Ubuntu:Pro:18.04:LTS","purl":"pkg:deb/ubuntu/libx11?arch=source&distro=esm-infra%2Fbionic"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:1.6.4-3ubuntu0.4+esm3"}]}],"versions":["2:1.6.4-3","2:1.6.4-3ubuntu0.1","2:1.6.4-3ubuntu0.2","2:1.6.4-3ubuntu0.3","2:1.6.4-3ubuntu0.4","2:1.6.4-3ubuntu0.4+esm1","2:1.6.4-3ubuntu0.4+esm2"],"ecosystem_specific":{"binaries":[{"binary_version":"2:1.6.4-3ubuntu0.4+esm3","binary_name":"libx11-6"},{"binary_name":"libx11-data","binary_version":"2:1.6.4-3ubuntu0.4+esm3"},{"binary_version":"2:1.6.4-3ubuntu0.4+esm3","binary_name":"libx11-xcb1"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"cves_map":{"cves":[{"id":"CVE-2026-88806","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}]},{"id":"CVE-2026-94283","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]},{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},{"score":"medium","type":"Ubuntu"}],"id":"CVE-2026-94284"},{"severity":[{"score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","type":"CVSS_V3"},{"score":"medium","type":"Ubuntu"}],"id":"CVE-2026-94285"}],"ecosystem":"Ubuntu:Pro:18.04:LTS"},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8913-1.json"}},{"package":{"name":"libx11","ecosystem":"Ubuntu:Pro:20.04:LTS","purl":"pkg:deb/ubuntu/libx11?arch=source&distro=esm-infra%2Ffocal"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:1.6.9-2ubuntu1.6+esm1"}]}],"versions":["2:1.6.8-1","2:1.6.9-2","2:1.6.9-2ubuntu1","2:1.6.9-2ubuntu1.1","2:1.6.9-2ubuntu1.2","2:1.6.9-2ubuntu1.5","2:1.6.9-2ubuntu1.6"],"ecosystem_specific":{"binaries":[{"binary_name":"libx11-6","binary_version":"2:1.6.9-2ubuntu1.6+esm1"},{"binary_name":"libx11-data","binary_version":"2:1.6.9-2ubuntu1.6+esm1"},{"binary_version":"2:1.6.9-2ubuntu1.6+esm1","binary_name":"libx11-xcb1"}],"availability":"Available with Ubuntu Pro (Infra-only): https://ubuntu.com/pro"},"database_specific":{"cves_map":{"cves":[{"id":"CVE-2026-88806","severity":[{"score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}]},{"id":"CVE-2026-94283","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}]},{"severity":[{"score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-94284"},{"id":"CVE-2026-94285","severity":[{"score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L","type":"CVSS_V3"},{"score":"medium","type":"Ubuntu"}]}],"ecosystem":"Ubuntu:Pro:20.04:LTS"},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8913-1.json"}},{"package":{"name":"libx11","ecosystem":"Ubuntu:22.04:LTS","purl":"pkg:deb/ubuntu/libx11?arch=source&distro=jammy"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:1.7.5-1ubuntu0.4"}]}],"versions":["2:1.7.2-1","2:1.7.2-2","2:1.7.2-2build1","2:1.7.5-1","2:1.7.5-1ubuntu0.2","2:1.7.5-1ubuntu0.3"],"ecosystem_specific":{"binaries":[{"binary_name":"libx11-6","binary_version":"2:1.7.5-1ubuntu0.4"},{"binary_version":"2:1.7.5-1ubuntu0.4","binary_name":"libx11-data"},{"binary_name":"libx11-xcb1","binary_version":"2:1.7.5-1ubuntu0.4"}],"availability":"No subscription required"},"database_specific":{"cves_map":{"cves":[{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-88806"},{"severity":[{"score":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H","type":"CVSS_V3"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-94283"},{"severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:N/I:N/A:H"},{"type":"Ubuntu","score":"medium"}],"id":"CVE-2026-94284"},{"id":"CVE-2026-94285","severity":[{"type":"CVSS_V3","score":"CVSS:3.1/AV:L/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:L"},{"score":"medium","type":"Ubuntu"}]}],"ecosystem":"Ubuntu:22.04:LTS"},"source":"https://github.com/canonical/ubuntu-security-notices/blob/main/osv/usn/USN-8913-1.json"}},{"package":{"name":"libx11","ecosystem":"Ubuntu:24.04:LTS","purl":"pkg:deb/ubuntu/libx11?arch=source&distro=noble"},"ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"fixed":"2:1.8.7-1ubuntu0.1"}]}],"versions":["2:1.8.6-1ubuntu1","2:1.8.7-1","2:1.8.7-1build1"],"ecosystem_specific":{"availability":"No 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