Summary
RustFS has SourceIp bypass via spoofed X-Forwarded-For/Real-IP headers
Impact
- Vulnerability type: Authorization bypass of IP-allowlist (
aws:SourceIp) via header spoofing.- Who is impacted: Any deployment relying on
aws:SourceIpin IAM/bucket policies for S3 operations. Attackers with network reach to RustFS can forge forwarded-IP headers to gain list/read/write where IP restrictions were meant to block them.
- Who is impacted: Any deployment relying on
Affected versions
rustfs (< 1.0.0-alpha.78)
Security releases
rustfs → 1.0.0-alpha.78 (rust)
Kodem intelligence
Severity tells you how bad this could be in the worst case. It does not tell you whether you are exposed. Exploitability and impact are functions of runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A vulnerable package can sit in your dependency tree and never run.
Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter. Kodem's runtime-powered SCA identifies whether this CVE is reachable in your applications.
Remediation advice
Upgrade rustfs to 1.0.0-alpha.78 or later to resolve this vulnerability.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Kodem Kai can prioritize this vulnerability in your dependency tree and generate a fix recommendation.
Frequently Asked Questions
- What is CVE-2026-21862? CVE-2026-21862 is a high-severity security vulnerability in rustfs (rust), affecting versions < 1.0.0-alpha.78. It is fixed in 1.0.0-alpha.78.
- Which versions of rustfs are affected by CVE-2026-21862? rustfs (rust) versions < 1.0.0-alpha.78 is affected.
- Is there a fix for CVE-2026-21862? Yes. CVE-2026-21862 is fixed in 1.0.0-alpha.78. Upgrade to this version or later.
- Is CVE-2026-21862 exploitable, and should I be worried? Whether CVE-2026-21862 is exploitable in your environment depends on whether the vulnerable code is present and reachable. A CVSS score is a worst-case rating; it does not account for your specific deployment, configuration, or usage patterns. Kodem, an Intelligent Application Security platform, uses runtime intelligence to show which vulnerabilities actually execute in production, so you can focus on the ones that represent real risk. Get a demo
- What actually determines whether CVE-2026-21862 is exploitable, and how bad it is? Exploitability and impact are not fixed properties of a CVE. They depend on runtime truth: whether the vulnerable code is present, reachable, and actually executes in your application. A high CVSS score on a dependency that never runs is not the same as real risk. Kodem, an Intelligent Application Security platform, uses runtime intelligence to reveal which vulnerabilities actually execute in production, so teams prioritize the ones that genuinely matter.
- How do I fix CVE-2026-21862? Upgrade
rustfsto 1.0.0-alpha.78 or later.