{"answers":{"affected":"2 open source packages ship an affected version, including rack.","exploited":"There is no known exploitation of CVE-2026-125109 in the wild and no public exploit code.","exposure":"","fix":"Upgrade rack to a fixed version for your release line: 3.1.23 or 3.2.8.","what":"CVE-2026-125109 is a medium-severity vulnerability in rack, published on 9 Nov 2026."},"fix_prompt":"Check this codebase for CVE-2026-125109 and fix it if it is affected.\n\nWhat it is: CVE-2026-125109 is a medium-severity vulnerability in rack, published on 9 Nov 2026. \nExploitation: There is no known exploitation of CVE-2026-125109 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- rack (RubyGems): affected from 3.0.0; fixed in 3.1.23\n- rack (RubyGems): affected from 3.2.0; fixed in 3.2.8\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-2026-125109/ (Markdown: https://insights.sbomify.com/CVE-2026-125109/index.md)","id":"CVE-2026-125109","markdown":"https://insights.sbomify.com/CVE-2026-125109/index.md","name":"CVE-2026-125109","record":{"aliases":["DEBIAN-CVE-2026-125109","GHSA-2j8w-xcrc-x985","UBUNTU-CVE-2026-125109"],"analysis":null,"analysis_generated_by":null,"assigner":"GitHub_M","cpe":[],"cvss":{"score":4.8,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:L/I:L/A:N","version":"3.1"},"cwes":[{"id":"CWE-1286","name":"Improper Validation of Syntactic Correctness of Input"}],"description":"Rack is a modular Ruby web server interface. From 3.0 until 3.1.23 and 3.2.8, Rack::Request#host_with_port, #base_url, and #url can return an attacker-controlled invalid authority from Host, X-Forwarded-Host, or Forwarded: host= verbatim. Applications without an independent host allowlist that use these methods for absolute URLs, redirects, or origin-dependent checks can emit attacker-chosen delimiters, enabling redirect manipulation, string-based allowlist bypass, or unescaped markup reflection. Rails overrides these methods and is not expected to be affected. This issue is fixed in versions 3.1.23 and 3.2.8.","ecosystems":["RubyGems"],"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":"Rack: Rack::Request#host_with_port (and #base_url / #url) return the raw invalid Host header — incomplete fix of CVE-2026-34835","id":"CVE-2026-125109","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"RubyGems","product":null,"products":[],"type":null,"year":"2026"},"n_packages":2,"n_references":5,"next":{"headline":"Rack: Rack::Static header_rules bypass via dot-segment normalization mismatch","id":"CVE-2026-125110"},"nickname":null,"packages":[{"ecosystem":"RubyGems","fixed":["3.1.23"],"introduced":["3.0.0"],"last_affected":[],"package":"rack","purl":null,"source":"GHSA-2j8w-xcrc-x985"},{"ecosystem":"RubyGems","fixed":["3.2.8"],"introduced":["3.2.0"],"last_affected":[],"package":"rack","purl":null,"source":"GHSA-2j8w-xcrc-x985"}],"prev":{"headline":"Rack: Multipart boundary ambiguity guard in Rack::Multipart::Parser can be bypassed with a quoted boundary value, allowing WAF bypass","id":"CVE-2026-125108"},"products":["rack"],"published":"2026-11-09","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":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-11-10","vendors":["rack"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-125109/"}