{"answers":{"affected":"It affects 1 product.","exploited":"There is no known exploitation of CVE-2026-73256 in the wild and no public exploit code.","fix":"Upgrade to a fixed version.","what":"CVE-2026-73256 is a critical vulnerability in Cesanta Mongoose, published on 20 Aug 2026."},"fix_prompt":"Check this codebase for CVE-2026-73256 and fix it if it is affected.\n\nWhat it is: CVE-2026-73256 is a critical vulnerability in Cesanta Mongoose, published on 20 Aug 2026. \nExploitation: There is no known exploitation of CVE-2026-73256 in the wild and no public exploit code.\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-2026-73256/ (Markdown: https://insights.sbomify.com/CVE-2026-73256/index.md)","id":"CVE-2026-73256","markdown":"https://insights.sbomify.com/CVE-2026-73256/index.md","name":"CVE-2026-73256","record":{"aliases":["DEBIAN-CVE-2026-73256","GHSA-mgp5-rjrv-h5j3","JLSEC-2026-1380","UBUNTU-CVE-2026-73256"],"analysis":null,"analysis_generated_by":null,"assigner":"GitHub_M","cpe":[{"product":"mongoose","vendor":"cesanta"}],"cvss":{"score":9.1,"severity":"critical","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N","version":"3.1"},"cwes":[{"id":"CWE-444","name":"Inconsistent Interpretation of HTTP Requests"}],"description":"Mongoose is an embedded web server and network library. Prior to 7.22, a remote unauthenticated attacker can exploit an HTTP/1.0 reverse-proxy deployment by sending a request with Transfer-Encoding: chunked and conflicting framing. The http_cb() function in src/http.c tests hm.proto.len with an impossible greater-than-eight condition even though mg_http_parse() requires an eight-byte protocol string, so is_http_1_0 is never set. Mongoose consequently processes chunked encoding that an HTTP/1.0 proxy can ignore, enabling request smuggling and unauthorized access or state changes. 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":"none_known"},"has_fix":true,"headline":"Mongoose: HTTP/1.0 detection off-by-one enables request smuggling via chunked TE","id":"CVE-2026-73256","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":"cesanta:mongoose","products":["cesanta:mongoose"],"type":null,"year":"2026"},"n_packages":0,"n_references":4,"next":{"headline":"Mongoose: Content-Length + Transfer-Encoding coexistence enables request smuggling","id":"CVE-2026-73257"},"packages":[],"prev":{"headline":"Mongoose: Path traversal in SSI #include directives enables arbitrary file read","id":"CVE-2026-73255"},"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":"yes","exploitation":"none","technical_impact":"total"},"state":"PUBLISHED","updated":"2026-08-21","vendors":["cesanta"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-73256/"}