{"answers":{"affected":"7 open source packages ship an affected version, including k8s.io/kubernetes. It affects 1 product.","exploited":"There is no known exploitation of CVE-2021-25735 in the wild and no public exploit code.","fix":"Upgrade k8s.io/kubernetes to a fixed version for your release line: 1.18.18, 1.19.10 or 1.20.6.","what":"CVE-2021-25735 is a medium-severity vulnerability in Kubernetes Kubernetes, published on 6 Sep 2021. An attacker needs administrator access to exploit it, with no action from the victim."},"fix_prompt":"Check this codebase for CVE-2021-25735 and fix it if it is affected.\n\nWhat it is: CVE-2021-25735 is a medium-severity vulnerability in Kubernetes Kubernetes, published on 6 Sep 2021. An attacker needs administrator access to exploit it, with no action from the victim.\nExploitation: There is no known exploitation of CVE-2021-25735 in the wild and no public exploit code.\n\nAffected packages and fixed versions:\n- k8s.io/kubernetes (Go): affected all versions; fixed in 1.18.18, 1.19.10, 1.20.6\n- k8s.io/kubernetes (Go): affected all versions; fixed in 1.18.18\n- k8s.io/kubernetes (Go): affected all versions; fixed in 1.18.18\n- k8s.io/kubernetes (Go): affected from 1.19.0; fixed in 1.19.10\n- k8s.io/kubernetes (Go): affected from 1.19.0; fixed in 1.19.10\n- k8s.io/kubernetes (Go): affected from 1.20.0; fixed in 1.20.6\n- k8s.io/kubernetes (Go): affected from 1.20.0; fixed in 1.20.6\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-2021-25735/ (Markdown: https://insights.sbomify.com/CVE-2021-25735/index.md)","id":"CVE-2021-25735","markdown":"https://insights.sbomify.com/CVE-2021-25735/index.md","name":"CVE-2021-25735","record":{"aliases":["CLEANSTART-2025-YC51954","DEBIAN-CVE-2021-25735","GHSA-g42g-737j-qx6j","GO-2022-0907"],"analysis":{"component_type":"container_or_infrastructure","fix_type":"upgrade","impacts":["security_bypass"],"network_reachable":"yes","non_default_config":true,"product_category":"Kubernetes API server","requires_auth":"high_privilege","summary":"Attackers can bypass Validating Admission Webhooks for Node updates if the webhook relies on previous object state, potentially allowing unauthorized node modifications.","user_interaction":"not_required","vuln_class":"security_feature_bypass"},"analysis_generated_by":"qwen3.8-flash-next","assigner":"kubernetes","cpe":[{"product":"kubernetes","vendor":"kubernetes"}],"cvss":{"score":6.5,"severity":"medium","source":"cna","vector":"CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:U/C:N/I:H/A:H","version":"3.1"},"cwes":[{"id":"CWE-372","name":"Incomplete Internal State Distinction"}],"description":"A security issue was discovered in kube-apiserver that could allow node updates to bypass a Validating Admission Webhook. Clusters are only affected by this vulnerability if they run a Validating Admission Webhook for Nodes that denies admission based at least partially on the old state of the Node object. Validating Admission Webhook does not observe some previous fields.","ecosystems":["Go"],"exploits":{"exploitdb":0,"first_seen":"2021-04-22","github_poc":1,"max_poc_stars":17,"metasploit":0,"nuclei":0,"refs":[{"date":"2021-04-22T07:25:31Z","kind":"github_poc","ref":"https://github.com/darryk10/CVE-2021-25735","stars":17,"title":"Exploit CVE-2021-25735: Kubernetes Validating Admission Webhook Bypass"}],"tier":"poc_unverified"},"has_fix":true,"headline":"Validating Admission Webhook does not observe some previous fields","id":"CVE-2021-25735","indexable":true,"kev":null,"kind":"cve","links":{"ecosystem":"Go","product":"kubernetes:kubernetes","products":["kubernetes:kubernetes"],"type":"security_feature_bypass","year":"2021"},"n_packages":7,"n_references":2,"next":{"headline":"Windows kube-proxy LoadBalancer contention","id":"CVE-2021-25736"},"packages":[{"ecosystem":"Go","fixed":["1.18.18","1.19.10","1.20.6"],"introduced":["0","1.19.0","1.20.0"],"last_affected":[],"package":"k8s.io/kubernetes","purl":"pkg:golang/k8s.io/kubernetes","source":"GO-2022-0907"},{"ecosystem":"Go","fixed":["1.18.18"],"introduced":["0"],"last_affected":[],"package":"k8s.io/kubernetes","purl":null,"source":"GHSA-g42g-737j-qx6j"},{"ecosystem":"Go","fixed":["1.18.18"],"introduced":["0"],"last_affected":[],"package":"k8s.io/kubernetes","purl":"pkg:golang/k8s.io/kubernetes","source":"GHSA-g42g-737j-qx6j"},{"ecosystem":"Go","fixed":["1.19.10"],"introduced":["1.19.0"],"last_affected":[],"package":"k8s.io/kubernetes","purl":null,"source":"GHSA-g42g-737j-qx6j"},{"ecosystem":"Go","fixed":["1.19.10"],"introduced":["1.19.0"],"last_affected":[],"package":"k8s.io/kubernetes","purl":"pkg:golang/k8s.io/kubernetes","source":"GHSA-g42g-737j-qx6j"},{"ecosystem":"Go","fixed":["1.20.6"],"introduced":["1.20.0"],"last_affected":[],"package":"k8s.io/kubernetes","purl":null,"source":"GHSA-g42g-737j-qx6j"},{"ecosystem":"Go","fixed":["1.20.6"],"introduced":["1.20.0"],"last_affected":[],"package":"k8s.io/kubernetes","purl":"pkg:golang/k8s.io/kubernetes","source":"GHSA-g42g-737j-qx6j"}],"prev":{"headline":"Denial of service in - PCoIP Software Client","id":"CVE-2021-25701"},"products":["Kubernetes"],"published":"2021-09-06","related":[{"cvss_score":9.8,"headline":"Privilege Escalation in Kubernetes","id":"CVE-2018-1002105","kev_date_added":null,"published":"2018-12-05"},{"cvss_score":9.8,"headline":"Kubernetes Privilege Escalation","id":"CVE-2017-1000056","kev_date_added":null,"published":"2017-07-13"},{"cvss_score":9.8,"headline":"Authorization bypass in Openshift","id":"CVE-2016-1906","kev_date_added":null,"published":"2016-02-03"},{"cvss_score":8.8,"headline":"Kubernetes - Windows nodes - Insufficient input sanitization leads to privilege escalation","id":"CVE-2023-3676","kev_date_added":null,"published":"2023-10-31"},{"cvss_score":8.8,"headline":"Kubernetes - Windows nodes - Insufficient input sanitization leads to privilege escalation","id":"CVE-2023-3955","kev_date_added":null,"published":"2023-10-31"},{"cvss_score":8.8,"headline":"Symlink Exchange Can Allow Host Filesystem Access","id":"CVE-2021-25741","kev_date_added":null,"published":"2021-09-20"},{"cvss_score":8.8,"headline":"Path traversal in Kubernetes","id":"CVE-2017-1002101","kev_date_added":null,"published":"2018-03-13"}],"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":"CC BY 4.0","name":"Go Vulnerability Database","prefix":"GO"},{"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)"},{"class":"open","licence":"CC0","name":"PoC-in-GitHub"}],"ssvc":{"automatable":null,"exploitation":null,"technical_impact":null},"state":"PUBLISHED","updated":"2024-09-16","vendors":["Kubernetes"]},"summary":"Attackers can bypass Validating Admission Webhooks for Node updates if the webhook relies on previous object state, potentially allowing unauthorized node modifications.","url":"https://insights.sbomify.com/CVE-2021-25735/"}