{"answers":{"affected":"2 open source packages ship an affected version, including unhead. It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31873 exists.","fix":"Upgrade unhead to 2.1.11 or later.","what":"CVE-2026-31873 is a cross-site scripting vulnerability in unjs unhead, published on 12 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2026-31873 and fix it if it is affected.\n\nWhat it is: CVE-2026-31873 is a cross-site scripting vulnerability in unjs unhead, published on 12 Mar 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-31873 exists.\n\nAffected packages and fixed versions:\n- unhead (npm): affected all versions; fixed in 2.1.11\n- unhead (npm): affected all versions; fixed in 2.1.11\n\nTask:\n1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.\n2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.\n3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.\n4. Run the tests and summarise what changed and why.\n5. If nothing in the project is affected, say so and change nothing.\n\nReference: https://insights.sbomify.com/CVE-2026-31873/ (Markdown: https://insights.sbomify.com/CVE-2026-31873/index.md)","id":"CVE-2026-31873","markdown":"https://insights.sbomify.com/CVE-2026-31873/index.md","name":"CVE-2026-31873","record":{"aliases":["GHSA-5339-hvwr-7582"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["data_read","security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"JavaScript head manager","requires_auth":"none","summary":"Attackers can bypass URI sanitization to inject malicious CSS, enabling UI redressing or data exfiltration in applications using Unhead.","user_interaction":"not_required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"unhead","vendor":"unjs"}],"cvss":{"score":0,"severity":"low","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:N","version":"3.1"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"description":"Unhead is a document head and template manager. Prior to 2.1.11, The link.href check in makeTagSafe (safe.ts) uses String.includes(), which is case-sensitive. Browsers treat URI schemes case-insensitively. DATA:text/css,... is the same as data:text/css,... to the browser, but 'DATA:...'.includes('data:') returns false. An attacker can inject arbitrary CSS for UI redressing or data exfiltration via CSS attribute selectors with background-image callbacks. This vulnerability is fixed in 2.1.11.","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Unhead has a Bypass of URI Scheme Sanitization in makeTagSafe via Case-Sensitivity","id":"CVE-2026-31873","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"xss","year":"2026"},"n_packages":2,"n_references":1,"next":{"headline":"Taskosaur Improper Role Assignment via Parameter Manipulation in User Registration","id":"CVE-2026-31874"},"packages":[{"ecosystem":"npm","fixed":["2.1.11"],"introduced":["0"],"last_affected":[],"package":"unhead","purl":null,"source":"GHSA-5339-hvwr-7582"},{"ecosystem":"npm","fixed":["2.1.11"],"introduced":["0"],"last_affected":[],"package":"unhead","purl":"pkg:npm/unhead","source":"GHSA-5339-hvwr-7582"}],"prev":{"headline":"Parse Server has a protected fields bypass via dot-notation in query and sort","id":"CVE-2026-31872"},"products":["unhead"],"published":"2026-03-12","related":[{"cvss_score":6.1,"headline":"Unhead has a hasDangerousProtocol() bypass via leading-zero padded HTML entities in useHeadSafe()","id":"CVE-2026-39315","kev_date_added":null,"published":"2026-04-09"},{"cvss_score":5.3,"headline":"Unhead has a XSS bypass in `useHeadSafe` via attribute name injection and case-sensitive protocol check","id":"CVE-2026-31860","kev_date_added":null,"published":"2026-03-12"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CC BY 4.0","name":"GitHub Advisory Database","prefix":"GHSA"},{"class":"attribution","licence":"US public information, NVD API terms","name":"NVD"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-03-12","vendors":["unjs"]},"summary":"Attackers can bypass URI sanitization to inject malicious CSS, enabling UI redressing or data exfiltration in applications using Unhead.","url":"https://insights.sbomify.com/CVE-2026-31873/"}