VDB
CVE-2026-31838
CVE-2026-31838
PUBLISHED
CVSS 6.900000095367432 MEDIUM
Istio is an open platform to connect, manage, and secure microservices. Prior to 1.29.1, 1.28.5, and 1.27.8, a vulnerability in Envoy RBAC header matching could allow authorization policy bypass when policies rely on HTTP headers that may contain multiple values. An attacker could craft requests with multiple header values in a way that causes Envoy to evaluate the header differently than intended, potentially bypassing authorization checks. This may allow unauthorized requests to reach protected services when policies depend on such header-based matching conditions. This vulnerability is fixed in 1.29.1, 1.28.5, and 1.27.8.
EPSS 0.04% · 11.4th percentile
Risk Scores
CVSS 4.0
6.900000095367432
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:N/VA:N/SC:L/SI:N/SA:N
EPSS Score
0.04%
11.4th percentile
Affected Products
| Vendor | Product | Versions |
|---|---|---|
| istio | istio | >= 1.29.0-alpha.0, < 1.29.1, >= 1.28.0-alpha.0, < 1.28.5, 0 |
Exploit Intelligence
- https://github.com/istio/istio/security/advisories/GHSA-974c-2wxh-g4ww (circl)
- CVE-2026-31838.json (github-poc)
- CVE-2026-31838.json (github-poc)
- CVE-2026-31838.json (github-poc)
- CVE-2026-31838.json (github-poc)
Timeline
- Mar 10, 2026 CVE Published
- Mar 11, 2026 EPSS Score
- Mar 12, 2026 EPSS Score
- Mar 13, 2026 EPSS Score
- Mar 14, 2026 EPSS Score
- Mar 15, 2026 EPSS Score
- Mar 16, 2026 EPSS Score
- Mar 17, 2026 EPSS Score
- Mar 17, 2026 Coalition ESS Score
- Mar 18, 2026 EPSS Score
- Mar 19, 2026 EPSS Score
- Mar 20, 2026 EPSS Score