{"answers":{"affected":"4 open source packages ship an affected version, including craftcms/cms. It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-31859 in the wild and no public exploit code.","fix":"Upgrade craftcms/cms to a fixed version for your release line: 4.17.3 or 5.9.7.","what":"CVE-2026-31859 is a medium-severity cross-site scripting vulnerability in Craftcms Craft Cms, published on 11 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-2026-31859 and fix it if it is affected.\n\nWhat it is: CVE-2026-31859 is a medium-severity cross-site scripting vulnerability in Craftcms Craft Cms, published on 11 Mar 2026. 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-2026-31859 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- craftcms/cms (Packagist): affected from 4.15.3; fixed in 4.17.3\n- craftcms/cms (Packagist): affected from 4.15.3; fixed in 4.17.3\n- craftcms/cms (Packagist): affected from 5.7.5; fixed in 5.9.7\n- craftcms/cms (Packagist): affected from 5.7.5; fixed in 5.9.7\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-2026-31859/ (Markdown: https://insights.sbomify.com/CVE-2026-31859/index.md)","id":"CVE-2026-31859","markdown":"https://insights.sbomify.com/CVE-2026-31859/index.md","name":"CVE-2026-31859","record":{"aliases":["GHSA-fvwq-45qv-xvhv"],"analysis":{"component_type":"web_application","fix_type":"upgrade","impacts":["code_execution","data_read"],"network_reachable":"yes","non_default_config":false,"product_category":"Craft CMS","requires_auth":"none","summary":"Attackers can execute arbitrary JavaScript in victim browsers via unsanitized return URLs, potentially stealing cookies or session data.","user_interaction":"not_required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"craft_cms","vendor":"craftcms"}],"cvss":{"score":6.9,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N","version":"4.0"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"},{"id":"CWE-116","name":"Improper Encoding or Escaping of Output"}],"description":"Craft is a content management system (CMS). The fix for CVE-2025-35939 in craftcms/cms introduced a strip_tags() call in src/web/User.php to sanitize return URLs before they are stored in the session. However, strip_tags() only removes HTML tags (angle brackets) -- it does not inspect or filter URL schemes. Payloads like javascript:alert(document.cookie) contain no HTML tags and pass through strip_tags() completely unmodified, enabling reflected XSS when the return URL is rendered in an href attribute. This vulnerability is fixed in  5.9.7 and 4.17.3.","ecosystems":["Packagist"],"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":"Craft has Reflective XSS via incomplete return URL sanitization","id":"CVE-2026-31859","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Packagist","product":"craftcms:craft_cms","products":["craftcms:craft_cms"],"type":"xss","year":"2026"},"n_packages":4,"n_references":1,"next":{"headline":"Unhead has a XSS bypass in `useHeadSafe` via attribute name injection and case-sensitive protocol check","id":"CVE-2026-31860"},"packages":[{"ecosystem":"Packagist","fixed":["4.17.3"],"introduced":["4.15.3"],"last_affected":[],"package":"craftcms/cms","purl":null,"source":"GHSA-fvwq-45qv-xvhv"},{"ecosystem":"Packagist","fixed":["4.17.3"],"introduced":["4.15.3"],"last_affected":[],"package":"craftcms/cms","purl":"pkg:composer/craftcms/cms","source":"GHSA-fvwq-45qv-xvhv"},{"ecosystem":"Packagist","fixed":["5.9.7"],"introduced":["5.7.5"],"last_affected":[],"package":"craftcms/cms","purl":null,"source":"GHSA-fvwq-45qv-xvhv"},{"ecosystem":"Packagist","fixed":["5.9.7"],"introduced":["5.7.5"],"last_affected":[],"package":"craftcms/cms","purl":"pkg:composer/craftcms/cms","source":"GHSA-fvwq-45qv-xvhv"}],"prev":{"headline":"CraftCMS's `ElementSearchController` Affected by Blind SQL Injection","id":"CVE-2026-31858"},"products":["cms"],"published":"2026-03-11","related":[{"cvss_score":10,"headline":"Craft CMS Code Injection","id":"CVE-2025-32432","kev_date_added":"2026-03-20","published":"2025-04-25"},{"cvss_score":9.3,"headline":"Craft CMS Code Injection","id":"CVE-2024-56145","kev_date_added":"2025-06-02","published":"2024-12-18"},{"cvss_score":8.1,"headline":"Craft CMS Code Injection","id":"CVE-2025-23209","kev_date_added":"2025-02-20","published":"2025-01-18"},{"cvss_score":6.9,"headline":"Craft CMS External Control of Assumed-Immutable Web Parameter","id":"CVE-2025-35939","kev_date_added":"2025-06-02","published":"2025-05-07"},{"cvss_score":10,"headline":"Craft CMS Remote Code Execution vulnerability","id":"CVE-2023-41892","kev_date_added":null,"published":"2023-09-13"},{"cvss_score":9.8,"headline":"Craft CMS Remote Code Injection","id":"CVE-2021-27903","kev_date_added":null,"published":"2021-06-30"},{"cvss_score":9.8,"headline":"SEOmatic for CraftCMS allows Server-Side Template Injection","id":"CVE-2020-9757","kev_date_added":null,"published":"2020-03-04"}],"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":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-03-12","vendors":["craftcms"]},"summary":"Attackers can execute arbitrary JavaScript in victim browsers via unsanitized return URLs, potentially stealing cookies or session data.","url":"https://insights.sbomify.com/CVE-2026-31859/"}