{"answers":{"affected":"","exploited":"There is no known exploitation of CVE-2026-121880 in the wild and no public exploit code.","exposure":"","fix":"No fix has been published for CVE-2026-121880 yet. Limit exposure of the affected software until one is available.","what":"CVE-2026-121880 is a medium-severity vulnerability in Posit Workbench, published on 6 Nov 2026."},"fix_prompt":"Check this codebase for CVE-2026-121880 and fix it if it is affected.\n\nWhat it is: CVE-2026-121880 is a medium-severity vulnerability in Posit Workbench, published on 6 Nov 2026. \nExploitation: There is no known exploitation of CVE-2026-121880 in the wild and no public exploit code.\n\nAffected product: Posit Workbench. 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-2026-121880/ (Markdown: https://insights.sbomify.com/CVE-2026-121880/index.md)","id":"CVE-2026-121880","markdown":"https://insights.sbomify.com/CVE-2026-121880/index.md","name":"CVE-2026-121880","record":{"aliases":["GHSA-45mx-vf84-77ww"],"analysis":null,"analysis_generated_by":null,"assigner":"POSIT","cpe":[],"cvss":{"score":4.7,"severity":"medium","source":"cna","vector":"CVSS:4.0/AV:L/AC:L/AT:P/PR:L/UI:N/VC:H/VI:N/VA:N/SC:N/SI:N/SA:N/E:P/AU:Y/R:A/V:D/RE:M/U:Amber","version":"4.0"},"cwes":[{"id":"CWE-862","name":"Missing Authorization"},{"id":"CWE-639","name":"Authorization Bypass Through User-Controlled Key"}],"description":"Authorization bypass through user-controlled key in the localhost port-proxy (/p/\u003ctoken\u003e/) in Posit Software, PBC RStudio Server and Posit Workbench before 2026.08.0 allows remote authenticated users to reach web applications and other services bound to 127.0.0.1 under a different user's session, and to view their live rendered content and data, via a proxy URL constructed from the attacker's own port token for an arbitrary port number. The port token is a documented obfuscation measure and not an authorization boundary, and the proxy does not verify that the requested port belongs to the requesting user's session.\n\nNOTE: exploitation requires an authenticated account on the same multi-user server and a target service listening on localhost at the time of access. Impact may be greater on hosts that co-locate additional privileged localhost services, and the bypass is not prevented by allow-shell=false; no setting restricts the port-proxy without disabling all application proxying.","ecosystems":[],"exploits":{"exploitdb":0,"first_seen":null,"github_poc":0,"max_poc_stars":null,"metasploit":0,"nuclei":0,"refs":[],"tier":"none_known"},"has_fix":null,"headline":"RStudio Server / Posit Workbench localhost port-proxy does not enforce per-session port ownership","id":"CVE-2026-121880","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":null,"product":null,"products":[],"type":null,"year":"2026"},"n_packages":0,"n_references":2,"next":{"headline":"Posit Workbench code-server session-state RPC (get_last_seen) SQL injection","id":"CVE-2026-121881"},"nickname":null,"packages":[],"prev":{"headline":"Security feature bypass in Red Hat Enterprise Linux 10","id":"CVE-2026-121876"},"products":["Posit Workbench","RStudio Server"],"published":"2026-11-06","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)"}],"ssvc":{"automatable":"no","exploitation":"none","technical_impact":"partial"},"state":"PUBLISHED","updated":"2026-11-06","vendors":["Posit Software, PBC"]},"summary":null,"url":"https://insights.sbomify.com/CVE-2026-121880/"}