{"cve":"CVE-2021-39156","nvd":{"published":"2021-08-24T23:15:10.413","modified":"2026-06-17T04:03:12.743","status":"Modified","description":"Istio is an open source platform for providing a uniform way to integrate microservices, manage traffic flow across microservices, enforce policies and aggregate telemetry data. Istio 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. Patches are available in Istio 1.11.1, Istio 1.10.4 and Istio 1.9.8. As a work around a Lua filter may be written to normalize the path.","cvss_v4":null,"cvss_v3":{"version":"3.1","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:N","score":7.5},"cwes":["CWE-706","CWE-863"],"references":["https://github.com/istio/istio/security/advisories/GHSA-hqxw-mm44-gc4r","https://istio.io/latest/news/security/istio-security-2021-008","https://github.com/istio/istio/security/advisories/GHSA-hqxw-mm44-gc4r","https://istio.io/latest/news/security/istio-security-2021-008"],"products":["istio:istio"],"source":"nvd","synced_at":"2026-10-19T21:21:57.125947417+00:00"},"epss":{"cve":"CVE-2021-39156","score":0.01167,"percentile":0.67347,"date":"2026-10-31"},"kev":null,"osv":[{"id":"GHSA-hqxw-mm44-gc4r","url":"https://osv.dev/vulnerability/GHSA-hqxw-mm44-gc4r","summary":"Istio Fragments in Path May Lead to Authorization Policy Bypass","modified":"2026-09-10T03:49:27.092104775Z","packages":[{"ecosystem":"Go","name":"istio.io/istio","purl":"pkg:golang/istio.io/istio","ranges":["<1.9.8"],"fixed":["1.9.8"]},{"ecosystem":"Go","name":"istio.io/istio","purl":"pkg:golang/istio.io/istio","ranges":[">=1.10.0 <1.10.4"],"fixed":["1.10.4"]},{"ecosystem":"Go","name":"istio.io/istio","purl":"pkg:golang/istio.io/istio","ranges":[">=1.11.0 <1.11.1"],"fixed":["1.11.1"]}]}],"attribution":["This product uses the NVD API but is not endorsed or certified by the NVD.","EPSS scores: FIRST Exploit Prediction Scoring System, https://www.first.org/epss","Known exploited vulnerabilities: CISA Known Exploited Vulnerabilities Catalog, https://www.cisa.gov/known-exploited-vulnerabilities-catalog","Package advisories: OSV (https://osv.dev), from the GitHub Advisory Database, PyPA, Go, RustSec and other ecosystem databases, under CC-BY 4.0 or CC0","CVE records: the CVE Program's CVE List (https://www.cve.org), under its terms of use (https://www.cve.org/Legal/TermsOfUse). CVE is a registered trademark of The MITRE Corporation; this product is not affiliated with the CVE Program."]}