{"answers":{"affected":"2 open source packages ship an affected version, including sanitize-html. It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-26540 in the wild and no public exploit code.","fix":"Upgrade sanitize-html to 2.3.2 or later.","what":"CVE-2021-26540 is a medium-severity vulnerability in n/a, published on 8 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-26540 and fix it if it is affected.\n\nWhat it is: CVE-2021-26540 is a medium-severity vulnerability in n/a, published on 8 Feb 2021. An attacker can exploit it over the internet without logging in, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-26540 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- sanitize-html (npm): affected all versions; fixed in 2.3.2\n- sanitize-html (npm): affected all versions; fixed in 2.3.2\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-2021-26540/ (Markdown: https://insights.sbomify.com/CVE-2021-26540/index.md)","id":"CVE-2021-26540","markdown":"https://insights.sbomify.com/CVE-2021-26540/index.md","name":"CVE-2021-26540","record":{"aliases":["GHSA-mjxr-4v3x-q3m4","ROOT-APP-NPM-CVE-2021-26540"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"sanitize-html npm library","requires_auth":"none","summary":"Attackers can bypass iframe hostname whitelists in sanitize-html when relative URLs are allowed, enabling unauthorized content embedding.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"mitre","cpe":[{"product":"sanitize-html","vendor":"apostrophecms"}],"cvss":{"score":5.3,"severity":"medium","source":"nvd","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:N","version":"3.1"},"cwes":[],"description":"Apostrophe Technologies sanitize-html before 2.3.2 does not properly validate the hostnames set by the \"allowedIframeHostnames\" option when the \"allowIframeRelativeUrls\" is set to true, which allows attackers to bypass hostname whitelist for iframe element, related using an src value that starts with \"/\\\\example.com\".","ecosystems":["npm"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":true,"headline":"Improper Input Validation in sanitize-html","id":"CVE-2021-26540","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"npm","product":null,"products":[],"type":"security_feature_bypass","year":"2021"},"n_packages":2,"n_references":3,"next":{"headline":"Command injection in gitlog","id":"CVE-2021-26541"},"packages":[{"ecosystem":"npm","fixed":["2.3.2"],"introduced":["0"],"last_affected":[],"package":"sanitize-html","purl":null,"source":"GHSA-mjxr-4v3x-q3m4"},{"ecosystem":"npm","fixed":["2.3.2"],"introduced":["0"],"last_affected":[],"package":"sanitize-html","purl":"pkg:npm/sanitize-html","source":"GHSA-mjxr-4v3x-q3m4"}],"prev":{"headline":"Improper Input Validation in sanitize-html","id":"CVE-2021-26539"},"products":["n/a"],"published":"2021-02-08","related":[{"cvss_score":6.1,"headline":"Cross-site scripting in apostrophecms:sanitize-html","id":"CVE-2014-125128","kev_date_added":null,"published":"2025-09-08"},{"cvss_score":6.1,"headline":"sanitize-html is vulnerable to XSS through incomprehensive sanitization","id":"CVE-2019-25225","kev_date_added":null,"published":"2025-09-08"},{"cvss_score":6.1,"headline":"Cross-Site Scripting in sanitize-html","id":"CVE-2016-1000237","kev_date_added":null,"published":"2020-01-23"},{"cvss_score":5.3,"headline":"sanitize-html Information Exposure vulnerability","id":"CVE-2024-21501","kev_date_added":null,"published":"2024-02-24"},{"cvss_score":5.3,"headline":"Regular Expression Denial of Service (ReDoS)","id":"CVE-2022-25887","kev_date_added":null,"published":"2022-08-30"},{"cvss_score":5.3,"headline":"Improper Input Validation in sanitize-html","id":"CVE-2021-26539","kev_date_added":null,"published":"2021-02-08"}],"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":"FIRST CVSS licence","name":"CVSS (FIRST)"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-08-03","vendors":["n/a"]},"summary":"Attackers can bypass iframe hostname whitelists in sanitize-html when relative URLs are allowed, enabling unauthorized content embedding.","url":"https://insights.sbomify.com/CVE-2021-26540/"}