CVE-2021-39156
Fragments in Path May Lead to Authorization Policy Bypass
Reported by github_m · Published August 24, 2021
github.com/istio/istio is fixed in 1.11.1, 1.10.3 and 1.9.8 (Go Modules)
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.
Fixed versions
Upgrade to a fixed version or later. Language registries are listed first, then Linux distributions, then vendor products.
| Package | Ecosystem | Fixed in |
|---|---|---|
| github.com/istio/istio | Go Modules | 1.11.1, 1.10.3, 1.9.8 |
| istio | Arch Linux | 1.11.1-1 |
| istio-operator-1.21 | Wolfi | 1.21.3-r0 |
| istio-operator-1.21 | Chainguard | 1.21.3-r0 |
| istio-pilot-agent-1.21 | Wolfi | 1.21.3-r0 |
| istio-cni-1.21 | Chainguard | 1.21.6-r8 |
| istio | istio | 1.11.1, 1.10.3, 1.9.8 |
Risk scores
Affected products
| Vendor | Product | Versions |
|---|---|---|
| istio | istio | < 1.9.8, >= 1.10.0, < 1.10.4, >= 1.11.0, < 1.11.1 |
| wolfi | istio-pilot-agent-1.22 | * |
| chainguard | cert-manager-istio-csr-fips | * |
| chainguard | istio-operator-1.22 | * |
| arch | istio | 0 |
| wolfi | istio-operator-1.21 | 0 |
| chainguard | kgateway-fips-2.4 | * |
| chainguard | istio-pilot-agent-1.22 | * |
| chainguard | istio-pilot-discovery-1.22 | * |
| chainguard | istio-operator-1.21 | 0 |
| github.com | istio/istio | 1.11.0, 1.10.0, 0 |
| wolfi | istio-operator-1.22 | * |
| wolfi | istio-pilot-agent-1.21 | 0 |
| chainguard | istio-cni-1.21 | 0 |
| istio | istio | 1.10.0, 0, 1.11.0 |
| chainguard | cert-manager-istio-csr | * |
| chainguard | istio-operator-1.20 | 0 |
| wolfi | istio-cni-1.22 | 0, * |
| chainguard | kgateway-fips-2.3 | * |
| wolfi | istio-cni-1.21 | 0 |
…and 11 more
Timeline
- Aug 24, 2021 CVE Published
- Aug 25, 2021 EPSS Score (30 in total, the first dated here)
- Aug 25, 2021 PoC Published (2 in total, the first dated here)
- Aug 15, 2022 CVE Updated
- Mar 19, 2026 Security Advisory
- Jul 23, 2026 Coalition ESS Score
Query this with the API
The same record, from the CLI:
vulnetix vdb vuln CVE-2021-39156
vulnetix vdb fixes CVE-2021-39156Or with curl, using the org id and key from your account page:
curl -s -H "Authorization: ApiKey ${VULNETIX_ORG_ID}:${VULNETIX_API_KEY}" \
"https://api.vdb.vulnetix.com/v2/vuln/CVE-2021-39156/fixes/registry"The Community plan is free and allows 50 queries a day. Get a free API key · API quickstart
References
- x_refsource_CONFIRM
- x_refsource_MISC
- https://github.com/advisories/GHSA-hqxw-mm44-gc4r advisory
- https://nvd.nist.gov/vuln/detail/CVE-2021-39156 advisory