VulnerabilityPublished 25 Feb 2026Updated 27 Feb 2026

CVE-2026-27739: angular-cli · Server-Side Request Forgery (SSRF)

Affects angular-cliSource CVE Database V5

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Not known to be exploited · CVSS 9.2 Critical · fixed in 21.2.0-rc.0 : patch angular-cli as a priority.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

9.2Critical

How severe the flaw is on the 0–10 CVSS scale.

Contested

Critical score, yet low EPSS after six months

EPSS: 0.5% chance of exploitation in 30 days – higher than 46% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 21.2.0-rc.0, 21.1.5, 20.3.17 +1

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:L/VA:N/SC:H/SI:L/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: None
Vulnerable system confidentiality: High
Vulnerable system integrity: Low
Vulnerable system availability: None
Subsequent system confidentiality: High
Subsequent system integrity: Low
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without interaction from any human user, other than the attacker.
Vulnerable system confidentiality: High: There is a total loss of confidentiality, resulting in all information within the Vulnerable System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Vulnerable system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: High: There is a total loss of confidentiality, resulting in all resources within the Subsequent System being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact. For example, an attacker steals the administrator's password, or private encryption keys of a web server.
Subsequent system integrity: Low: Modification of data is possible, but the attacker does not have control over the consequence of a modification, or the amount of modification is limited. The data modification does not have a direct, serious impact to the Subsequent System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 25 Feb 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
Public exploit code: GitHub proofs of concept
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), GitHub proofs of concept, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade angular-cli to 21.2.0-rc.0, 21.1.5, 20.3.17 or 19.2.21; angular-cli to 19.2.21.

Affected software

Product	Affected	Fixed in
angularangular-cli	Affected >=21.2.0-next.2 <21.2.0-rc.0	Fixed in 21.2.0-rc.0
angularangular-cli	Affected >=21.0.0-next.0 <21.1.5	Fixed in 21.1.5
angularangular-cli	Affected >=20.0.0-next.0 <20.3.17	Fixed in 20.3.17
angularangular-cli	Affected <19.2.21	Fixed in 19.2.21
angular@nguniversal/common	Affected <=16.2.0	Fixed in–
angular@nguniversal/express-engine	Affected <=16.2.0	Fixed in–

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

AI-suggested

To mitigate CVE-2026-27739, organizations should immediately upgrade Angular CLI and Angular SSR to versions 21.2.0-rc.1, 21.1.5, 20.3.17, or 19.2.21 or later, where the vulnerability is patched. If immediate upgrade is not feasible, implement middleware in the server.ts file to strictly validate and sanitize incoming Host and X-Forwarded-* headers, enforcing allowed hostnames and numeric port ranges. Avoid constructing URLs for HttpClient requests using untrusted headers such as req.headers; instead, use hardcoded or environment-configured trusted base URLs. Ensure that front-facing proxies, load balancers, CDNs, or cloud infrastructure sanitize or reject suspicious or malformed headers to prevent attacker-controlled header injection. Conduct thorough code reviews to identify any manual URL constructions relying on unvalidated headers and refactor them accordingly. Employ network segmentation and internal service authentication to limit the impact of SSRF if exploited. Monitor logs for unusual internal requests originating from SSR components. Finally, educate developers about the risks of trusting client-supplied headers in server-side rendering contexts.

Description

The Angular SSR is a server-rise rendering tool for Angular applications. Versions prior to 21.2.0-rc.1, 21.1.5, 20.3.17, and 19.2.21 have a Server-Side Request Forgery (SSRF) vulnerability in the Angular SSR request handling pipeline. The vulnerability exists because Angular’s internal URL reconstruction logic directly trusts and consumes user-controlled HTTP headers specifically the Host and `X-Forwarded-*` family to determine the application's base origin without any validation of the destination domain. Specifically, the framework didn't have checks for the host domain, path and character sanitization, and port validation. This vulnerability manifests in two primary ways: implicit relative URL resolution and explicit manual construction. When successfully exploited, this vulnerability allows for arbitrary internal request steering. This can lead to credential exfiltration, internal network probing, and a confidentiality breach. In order to be vulnerable, the victim application must use Angular SSR (Server-Side Rendering), the application must perform `HttpClient` requests using relative URLs OR manually construct URLs using the unvalidated `Host` / `X-Forwarded-*` headers using the `REQUEST` object, the application server must be reachable by an attacker who can influence these headers without strict validation from a front-facing proxy, and the infrastructure (Cloud, CDN, or Load Balancer) must not sanitize or validate incoming headers. Versions 21.2.0-rc.1, 21.1.5, 20.3.17, and 19.2.21 contain a patch. Some workarounds are available. Avoid using `req.headers` for URL construction. Instead, use trusted variables for base API paths. Those who cannot upgrade immediately should implement a middleware in their `server.ts` to enforce numeric ports and validated hostnames.

Impact

The impact of CVE-2026-27739 is significant for organizations using Angular SSR in vulnerable versions. Successful exploitation allows attackers to perform SSRF attacks, enabling them to send arbitrary HTTP requests from the server to internal or external systems. This can lead to internal network reconnaissance, exposing sensitive infrastructure details, and potentially pivoting attacks deeper into the network. Credential exfiltration is possible if internal services expose sensitive tokens or secrets accessible via SSRF. Confidentiality breaches may occur if internal-only services or data stores are accessed. Since SSRF can bypass perimeter defenses by leveraging the server's network access, it poses a high risk to cloud-hosted applications and microservice architectures. Organizations relying on Angular SSR without proper header validation or infrastructure sanitization are at risk of data leakage, service disruption, and further compromise. The vulnerability's critical severity and no requirement for authentication or user interaction make it a high-priority issue for affected environments.

CWE-918Server-Side Request Forgery (opens in a new tab)
Base weaknessCWE Top 25 (2025): #22OWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web server receives a URL or similar request from an upstream component and retrieves the contents of this URL, but it does not sufficiently ensure that the request is being sent to the expected destination.
Implementation · Operation
If there is a known list of applications, IP, hostname, and/or domains to which the product is allowed to communicate, then use allowlists to ensure that outgoing requests are restricted to these known entities. The allowlists could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Operation
If the product is expected to be able to connect to arbitrary IP addresses or domains, consider using a denylist that includes private network addresses, internal domain names, etc. The denylist could be in the application code or possibly enforced by firewalls or network segmentation.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
OWASP Cheat Sheets
Server Side Request Forgery Prevention (opens in a new tab)
Unvalidated Redirects and Forwards (opens in a new tab)
Cross Site Scripting Prevention (opens in a new tab)
DOM based XSS Prevention (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V12.6.1 (opens in a new tab)
V5.2.6 (opens in a new tab)
Attack patterns
Server Side Request Forgery (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

References

Community reviews

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Exploitation evidence

What to do

Affected software

Description

AI analysisMachine-generated, updated 5 Mar 2026, 09:51 UTC

Public exploits and detectionGitHub proofs of concept

WeaknessesCWE-918

Technical details

References

Community reviews

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