{"answers":{"affected":"It affects 1 product.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73259 exists.","fix":"Upgrade to a fixed version.","what":"CVE-2026-73259 is a medium-severity cross-site scripting vulnerability in Cesanta Mongoose, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link."},"fix_prompt":"Check this codebase for CVE-2026-73259 and fix it if it is affected.\n\nWhat it is: CVE-2026-73259 is a medium-severity cross-site scripting vulnerability in Cesanta Mongoose, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, and only if a user opens a file or follows a link.\nExploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-73259 exists.\n\nAffected product: Cesanta Mongoose. No package-level version data is available, so check the vendor advisory linked from the reference page.\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-2026-73259/ (Markdown: https://insights.sbomify.com/CVE-2026-73259/index.md)","id":"CVE-2026-73259","markdown":"https://insights.sbomify.com/CVE-2026-73259/index.md","name":"CVE-2026-73259","record":{"aliases":["DEBIAN-CVE-2026-73259","GHSA-9cwm-487w-h25w","JLSEC-2026-1383","UBUNTU-CVE-2026-73259"],"analysis":{"component_type":"server_software","fix_type":"upgrade","impacts":["data_read","account_takeover"],"network_reachable":"yes","non_default_config":true,"product_category":"Mongoose web server","requires_auth":"none","summary":"Attackers can execute scripts in victim browsers via crafted URLs in Mongoose directory listings, potentially stealing session data or performing actions.","user_interaction":"required","vuln_class":"xss"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"GitHub_M","cpe":[{"product":"mongoose","vendor":"cesanta"}],"cvss":{"score":5.4,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-79","name":"Improper Neutralization of Input During Web Page Generation"}],"description":"Mongoose is an embedded web server and network library. Prior to 7.22, a remote attacker can send a crafted percent-encoded request path to a deployment using MG_ENABLE_DIRLIST and persuade a user to visit it. The mg_http_serve_dir() and listdir() path in src/http.c places the decoded request URI into the title and h1 elements without HTML entity encoding. The resulting reflected cross-site scripting executes in the Mongoose origin and can expose session data or perform actions as the victim. This issue is fixed in version 7.22.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Mongoose: Reflected XSS via decoded URI in directory listing render","id":"CVE-2026-73259","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"cesanta:mongoose","products":["cesanta:mongoose"],"type":"xss","year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"Mongoose: Out-of-bounds Read via length-counter underflow in built-in TLS X.509 DER parser","id":"CVE-2026-73260"},"packages":[],"prev":{"headline":"Mongoose: Multipart boundary/header scan logic error in mg_http_next_multipart","id":"CVE-2026-73258"},"products":["mongoose"],"published":"2026-08-20","related":[{"cvss_score":9.8,"headline":"Arbitrary File Write","id":"CVE-2022-25299","kev_date_added":null,"published":"2022-02-18"},{"cvss_score":9.8,"headline":"Memory corruption in n/a","id":"CVE-2020-25756","kev_date_added":null,"published":"2020-09-18"},{"cvss_score":9.8,"headline":"Integer overflow in n/a","id":"CVE-2019-19307","kev_date_added":null,"published":"2019-11-26"},{"cvss_score":9.8,"headline":"Memory corruption in n/a","id":"CVE-2019-12951","kev_date_added":null,"published":"2019-06-24"},{"cvss_score":9.8,"headline":"Use after free in n/a","id":"CVE-2018-20353","kev_date_added":null,"published":"2019-06-10"},{"cvss_score":9.8,"headline":"Use after free in n/a","id":"CVE-2018-20354","kev_date_added":null,"published":"2019-06-10"},{"cvss_score":9.8,"headline":"Use after free in n/a","id":"CVE-2018-20355","kev_date_added":null,"published":"2019-06-10"}],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"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":"no","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-08-20","vendors":["cesanta"]},"summary":"Attackers can execute scripts in victim browsers via crafted URLs in Mongoose directory listings, potentially stealing session data or performing actions.","url":"https://insights.sbomify.com/CVE-2026-73259/"}