{"id":"CVE-2021-39156","aliases":["GHSA-hqxw-mm44-gc4r"],"url":"https://o3.security/vulnerability/CVE-2021-39156","summary":"Istio Fragments in Path May Lead to Authorization Policy Bypass","details":"### Impact\nIstio 1.11.0, 1.10.3 and below, and 1.9.7 and below contain a remotely exploitable vulnerability where an HTTP request with `#fragment` in the path may bypass Istio’s URI path based authorization policies. \n\n### Patches\n* Istio 1.11.1 and above\n* Istio 1.10.4 and above\n* Istio 1.9.8 and above\n\n### Workarounds\nA Lua filter may be written to normalize the path.  This is similar to the Path normalization presented in the [Security Best Practices](https://istio.io/latest/docs/ops/best-practices/security/#case-normalization) guide.\n\n### References\nMore details can be found in the [Istio Security Bulletin](https://istio.io/latest/news/security/istio-security-2021-008)\n\n### For more information\nIf you have any questions or comments about this advisory, please email us at istio-security-vulnerability-reports@googlegroups.com\n","published":"2021-08-24T23:15:10.413Z","modified":"2026-07-09T10:21:00.770562Z","cvss":{"score":7.5,"severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N"},"epss":null,"cisaKev":null,"exploitsKnown":0,"affectedPackages":[{"ecosystem":"Go","name":"istio.io/istio","fixedVersion":"1.9.8"},{"ecosystem":"Go","name":"istio.io/istio","fixedVersion":"1.10.4"},{"ecosystem":"Go","name":"istio.io/istio","fixedVersion":"1.11.1"}],"fix":null,"references":[{"type":"ADVISORY","url":"https://github.com/istio/istio/security/advisories/GHSA-hqxw-mm44-gc4r"},{"type":"ADVISORY","url":"https://istio.io/latest/news/security/istio-security-2021-008"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2021-39156"},{"type":"PACKAGE","url":"https://github.com/istio/istio"}],"provenance":{"sources":["OSV.dev","FIRST.org (EPSS)"],"lastVerified":"2026-07-09T10:21:00.770562Z"}}