{"answers":{"affected":"2 open source packages ship an affected version, including tornado.","exploited":"It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-91991 exists.","fix":"Upgrade tornado to 6.5.8 or later.","what":"CVE-2026-91991 is a medium-severity vulnerability in tornadoweb tornado, published on 15 Sep 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-2026-91991 and fix it if it is affected.\n\nWhat it is: CVE-2026-91991 is a medium-severity vulnerability in tornadoweb tornado, published on 15 Sep 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-2026-91991 exists.\n\nAffected packages and fixed versions:\n- tornado (PyPI): affected from 6.5.5; fixed in 6.5.8\n- tornado (PyPI): affected from 6.5.5; fixed in 6.5.8\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-2026-91991/ (Markdown: https://insights.sbomify.com/CVE-2026-91991/index.md)","id":"CVE-2026-91991","markdown":"https://insights.sbomify.com/CVE-2026-91991/index.md","name":"CVE-2026-91991","record":{"aliases":["BELL-CVE-2026-91991","CLEANSTART-2026-FR34222","CLEANSTART-2026-MS68027","CLEANSTART-2026-NF84390","CLEANSTART-2026-OZ84157","CLEANSTART-2026-RK84502","DEBIAN-CVE-2026-91991","ECHO-b37c-7c95-fabf","GHSA-jj9x-pjq2-f55m","GHSA-wwv5-g3v4-889x","MINI-37m9-mmr2-hpqv","MINI-475w-g7hr-vc2r","MINI-48g8-63f7-2hh3","MINI-78x6-39mx-fcvv","MINI-7w9h-rfmg-8hfp","MINI-8fcv-x33q-q2x8","MINI-8pqw-4f4q-4292","MINI-8pxg-wqx5-76ww","MINI-9jvg-q396-qv72","MINI-c9hj-rh9m-hcxv","MINI-cwg8-5vhc-hpwq","MINI-gqhm-6vm3-9xj8","MINI-hgrf-hvw4-f6cr","MINI-hrhq-m4pp-g64v","MINI-m84q-wwmp-6mjm","MINI-qcwh-qh3w-m782","MINI-qgr8-vxw9-957r","MINI-r2fx-2jr5-5j94","MINI-rxcm-gm76-3fmc","MINI-v5gx-f627-j4pm","MINI-w9h5-vx53-m83g","MINI-x378-ccgc-497x","MINI-xgf5-xqf8-v3v5","MINI-xhx2-38r9-cc38","UBUNTU-CVE-2026-91991"],"analysis":{"component_type":"library","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":false,"product_category":"Python web framework","requires_auth":"none","summary":"Attackers can inject arbitrary cookie attributes via capitalized kwargs in Tornado, bypassing security validation and modifying cookie settings.","user_interaction":"not_required","vuln_class":"other"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"VulnCheck","cpe":[],"cvss":{"score":6.3,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:N/AC:H/AT:P/PR:N/UI:N/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N","version":"4.0"},"cwes":[{"id":"CWE-113","name":"Improper Neutralization of CRLF Sequences in HTTP Headers"}],"description":"Tornado before 6.5.8 contains an incomplete fix for cookie attribute injection that allows attackers to inject arbitrary cookie attributes by passing capitalized or legacy keyword arguments to set_cookie. Attackers can embed semicolon-delimited data in capitalized parameters like Domain, Path, or SameSite to bypass validation and modify cookie security attributes.","ecosystems":["PyPI"],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"weaponised"},"has_fix":true,"headline":"Tornado before 6.5.8 Cookie Attribute Injection via Capitalized kwargs","id":"CVE-2026-91991","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"PyPI","product":null,"products":[],"type":"other","year":"2026"},"n_packages":2,"n_references":2,"next":{"headline":"Tornado before 6.5.7 Credential Leak via Handle Reuse","id":"CVE-2026-91992"},"packages":[{"ecosystem":"PyPI","fixed":["6.5.8"],"introduced":["6.5.5"],"last_affected":[],"package":"tornado","purl":null,"source":"GHSA-wwv5-g3v4-889x"},{"ecosystem":"PyPI","fixed":["6.5.8"],"introduced":["6.5.5"],"last_affected":[],"package":"tornado","purl":"pkg:pypi/tornado","source":"GHSA-wwv5-g3v4-889x"}],"prev":{"headline":"Tornado before 6.5.8 Memory Amplification DoS via multipart","id":"CVE-2026-91990"},"products":["tornado"],"published":"2026-09-15","related":[],"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":"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":"2026-10-08","vendors":["tornadoweb"]},"summary":"Attackers can inject arbitrary cookie attributes via capitalized kwargs in Tornado, bypassing security validation and modifying cookie settings.","url":"https://insights.sbomify.com/CVE-2026-91991/"}