{"answers":{"affected":"","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-66731 exists.","fix":"No fix has been published for CVE-2026-66731 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-66731 is a high-severity denial of service vulnerability in boazsegev facil.io, published on 27 Jul 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-2026-66731 and fix it if it is affected.\n\nWhat it is: CVE-2026-66731 is a high-severity denial of service vulnerability in boazsegev facil.io, published on 27 Jul 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-2026-66731 exists.\n\nAffected product: boazsegev facil.io. 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-2026-66731/ (Markdown: https://insights.sbomify.com/CVE-2026-66731/index.md)","id":"CVE-2026-66731","markdown":"https://insights.sbomify.com/CVE-2026-66731/index.md","name":"CVE-2026-66731","record":{"aliases":["GHSA-vg6c-748h-g68q"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["denial_of_service"],"network_reachable":"yes","non_default_config":false,"product_category":"facil.io HTTP library","requires_auth":"none","summary":"Remote attackers can crash the server by sending a malformed chunked request with a negative size, causing a memory fault in the parser.","user_interaction":"not_required","vuln_class":"denial_of_service"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[],"cvss":{"score":8.7,"severity":"high","source":"cna","vector":"CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N","version":"4.0"},"cwes":[{"id":"CWE-125","name":"Out-of-bounds Read"}],"description":"facil.io 0.7.5 through 0.7.6 contains a denial-of-service vulnerability in the HTTP/1.1 chunked transfer encoding parser that allows unauthenticated remote attackers to crash the server by sending a negative chunk size value. Attackers can send a single POST request with a Transfer-Encoding: chunked header containing a leading minus sign in the chunk size field, causing the parser in http1_parser.h to compute a large positive integer from the negated value, corrupting internal state and moving the read pointer into unmapped memory resulting in a fault.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":"2026-07-24","github_poc":1,"max_poc_stars":0,"metasploit":0,"nuclei":0,"refs":[{"date":"2026-07-24T22:28:38Z","kind":"github_poc","ref":"https://github.com/theopaid/CVE-2026-66731-Negative-Chunk-Size-Parsing-Causes-Memory-Corruption-leading-to-Server-Crash","stars":0,"title":"Security Advisory: Negative Chunk-Size Parsing Causes Memory Corruption in facil.io"}],"tier":"weaponised"},"has_fix":false,"headline":"facil.io 0.7.5 - 0.7.6 HTTP/1.1 Chunked Transfer Encoding Parser Crash DoS","id":"CVE-2026-66731","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":"denial_of_service","year":"2026"},"n_packages":0,"n_references":3,"next":{"headline":"Sonic 3 A.I.R. Missing Source Address Validation in ConnectionManager","id":"CVE-2026-66732"},"packages":[],"prev":{"headline":"facil.io 0.6.0 - 0.7.6 Infinite Loop DoS via Multipart MIME Body Parser","id":"CVE-2026-66730"},"products":["facil.io"],"published":"2026-07-27","related":[],"sources":[{"class":"attribution","licence":"CVE Terms of Use (MITRE)","name":"CVE List","prefix":"CVE"},{"class":"attribution","licence":"CWE Terms of Use","name":"CWE (MITRE)"},{"class":"attribution","licence":"FIRST CVSS licence","name":"CVSS (FIRST)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":"yes","exploitation":"poc","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-07-31","vendors":["boazsegev"]},"summary":"Remote attackers can crash the server by sending a malformed chunked request with a negative size, causing a memory fault in the parser.","url":"https://insights.sbomify.com/CVE-2026-66731/"}