{"id":"CVE-2026-59710","aliases":["EUVD-2026-41954","GHSA-22g5-r2x5-97cx"],"status":"published","title":"showdown - Stored XSS via Unescaped Table Header ID Attribute Injection","description":"showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.","severity":{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna","from":"cve"},"epss":{"day":"2026-11-09","score":0.00338,"percentile":0.27396,"model":"v2026.06.15"},"facts":{"in_kev":false,"known_exploited":false,"public_exploit":false,"fix_available":false},"cwes":["CWE-79"],"published":"2026-07-06T21:15:45Z","modified":"2026-10-28T02:30:32Z","affected":[{"source":"ghsa","ecosystem":"npm","package":"showdown","ranges":[{"type":"ECOSYSTEM","events":[{"introduced":"0"},{"last_affected":"2.1.0"}]}]},{"source":"osv","ecosystem":"npm","package":"showdown","ranges":[{"type":"SEMVER","events":[{"introduced":"0"},{"last_affected":"2.1.0"}]}]}],"products":[{"vendor":"showdown","product":"showdown"},{"vendor":"showdownjs","product":"showdown"}],"references":[{"url":"https://github.com/showdownjs/showdown/issues/1046","tags":["issue-tracking","exploit","report","web"]},{"url":"https://github.com/showdownjs/showdown","tags":["product","package"]},{"url":"https://github.com/showdownjs/showdown/commit/e5cab1e9a5dcea2bb3cbf888863fa7e65ab37edf","tags":["patch","fix","web"]},{"url":"https://www.vulncheck.com/advisories/showdown-stored-xss-via-unescaped-table-header-id-attribute-injection","tags":["third-party-advisory","advisory","web"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-59710","tags":["advisory"]},{"url":"https://github.com/advisories/GHSA-22g5-r2x5-97cx"},{"url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/59xxx/CVE-2026-59710.json","tags":["advisory"]}],"sources":{"cve":[{"id":"CVE-2026-59710","title":"showdown - Stored XSS via Unescaped Table Header ID Attribute Injection","description":"showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.","status":"published","published":"2026-07-06T21:15:45.9Z","modified":"2026-07-07T13:47:54.393Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium","assessor":"cna"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"cna"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:19:58.560602Z"}],"euvd":[{"id":"EUVD-2026-41954","description":"showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.","status":"published","published":"2026-07-06T21:15:45Z","modified":"2026-07-07T13:47:54Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"updated_at":"2026-11-02T18:20:11.925616Z"}],"ghsa":[{"id":"GHSA-22g5-r2x5-97cx","title":"showdown allows stored cross-site scripting through table header ID injection","description":"showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.","status":"published","published":"2026-07-07T00:30:59Z","modified":"2026-08-07T21:03:44Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"},{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:40:58.888637Z"}],"nvd":[{"id":"CVE-2026-59710","description":"showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.","status":"published","published":"2026-07-06T22:16:50.977Z","modified":"2026-07-07T13:57:49.473Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X","level":"medium","assessor":"secondary"},{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium","assessor":"secondary"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T14:12:28.040501Z"}],"osv":[{"id":"CVE-2026-59710","title":"showdown - Stored XSS via Unescaped Table Header ID Attribute Injection","description":"showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.","status":"published","published":"2026-07-06T21:15:45.9Z","modified":"2026-10-28T02:30:32.85016254Z","cvss":[{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:45:12.496548Z"},{"id":"GHSA-22g5-r2x5-97cx","title":"showdown allows stored cross-site scripting through table header ID injection","description":"showdown contains a stored cross-site scripting vulnerability in the parseHeaders function of src/subParsers/makehtml/tables.js that fails to properly escape table header ID attributes. Attackers can inject arbitrary HTML and script-executing SVG elements through double-quote characters in markdown table headers, achieving stored XSS when untrusted markdown is rendered with the default github flavor configuration.","status":"published","published":"2026-07-07T00:30:59Z","modified":"2026-09-10T03:51:09.845674087Z","cvss":[{"version":"3.1","score":6.1,"vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N","level":"medium"},{"version":"4.0","score":5.3,"vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","level":"medium"}],"cwes":["CWE-79"],"updated_at":"2026-11-02T15:46:33.520522Z"}]}}