Unauthenticated SSRF via unvalidated proxy headers
Published Feb 25, 2026 · Updated Feb 25, 2026
SSRF in affected Angular SSR releases allows remote attackers to steer server-side requests by supplying crafted proxy headers. The request pipeline trusts Host and X-Forwarded header values when reconstructing the base origin, then resolves relative HttpClient URLs or exposes the values through REQUEST without destination, path, character, or port validation. Exploitation requires an SSR application that uses one of those URL paths, permits attacker-controlled headers past its front proxy, and can reach sensitive internal services or an attacker-controlled endpoint, enabling internal probing and data or credential disclosure.
Summary
What happened
SSRF in affected Angular SSR releases allows remote attackers to steer server-side requests by supplying crafted proxy headers. The request pipeline trusts Host and X-Forwarded header values when reconstructing the base origin, then resolves relative HttpClient URLs or exposes the values through REQUEST without destination, path, character, or port validation. Exploitation requires an SSR application that uses one of those URL paths, permits attacker-controlled headers past its front proxy, and can reach sensitive internal services or an attacker-controlled endpoint, enabling internal probing and data or credential disclosure.
The record
- CVE
- CVE-2026-27739
- Published
- Feb 25, 2026
- Updated
- Feb 25, 2026
- Vendor
- Angular
- Product
- Angular CLI
- Classifications
- CWE-918, T1552.005, T1046
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Feb 25, 2026CVE publishedPublication date reported by the CVE source.
- Feb 25, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 19.2.21
- Affected versionversion=>= 20.0.0-next.0, < 20.3.17
- Affected versionversion=>= 21.0.0-next.0, < 21.1.5
- Affected versionversion=>= 21.2.0-next.2, < 21.2.0-rc.0
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
No public exploit references are available in this record.
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo