CVE-2026-27738

MEDIUMPre-NVD 6.96.9—
EchelonGraph scoreMEDIUM confidence

This medium-severity CVE scores 6.9 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit probability: 0.3%, top 77% of all CVEs by exploit prediction. GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: epss, secondary
Elevated
6.9EG
EchelonGraph verdictMonitorLow exploitation likelihood right now — keep watching.
  • Lower severity and no public exploit yet
CISA-KEV: Not listedEPSS PROB: 0%CVSS: 6.9Exploit: Elevated riskExposed: 0

No vendor fix yet — apply a workaround or compensating control (WAF / firewall / segmentation) and watch for a patch.

The Angular SSR is a server-rise rendering tool for Angular applications. An Open Redirect vulnerability exists in the internal URL processing logic in versions on the 19.x branch prior to 19.2.21, the 20.x branch prior to 20.3.17, and the 21.x branch prior to 21.1.5 and 21.2.0-rc.1. The logic normalizes URL segments by stripping leading slashes; however, it only removes a single leading slash. When an Angular SSR application is deployed behind a proxy that passes the X-Forwarded-Prefix header, an attacker can provide a value starting with three slashes. This vulnerability allows attackers to conduct large-scale phishing and SEO hijacking. In order to be vulnerable, the application must use Angular SSR, the application must have routes that perform internal redirects, the infrastructure (Reverse Proxy/CDN) must pass the X-Forwarded-Prefix header to the SSR process without sanitization, and the cache must not vary on the X-Forwarded-Prefix header. Versions 21.2.0-rc.1, 21.1.5, 20.3.17, and 19.2.21 contain a patch. Until the patch is applied, developers should sanitize the X-Forwarded-Prefix header in theirserver.ts before the Angular engine processes the request.

CVSS v3
6.9
EG Score
6.9(medium)
EG Risk
62(Attend)
EG Risk 62/100SSVC: Attend

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity69% × 45%
Exploitation40% × 40%
Automatability100% × 15%
Action: Remediate soon — notable exploitation risk.
EPSS PROB
0%
EPSS %ILE
23%
KEV
Not listed

Published

February 25, 2026

Last Modified

June 17, 2026

Advisory Details (4)

Auto-updated Aug 4, 2026
Patch available. Sources: github_commit, github_pr, github.
generic

Open Redirect via Unsanitized X-Forwarded-Prefix Header, Chainable to Web Cache Poisoning · Issue #32501 · angular/angular-cli · GitHub

https://github.com/angular/angular-cli/issues/32501
github Patch Available

Open Redirect via X-Forwarded-Prefix in Angular SSR · Advisory · angular/angular-cli · GitHub

https://github.com/angular/angular-cli/security/advisories/GHSA-xh43-g2fq-wjrj
github_pr Patch Available

fix(@angular/ssr): prevent open redirect via X-Forwarded-Prefix header

Patch available: angular/angular-cli v22.0.0 (PR #32521 merged 2026-02-23)

https://github.com/angular/angular-cli/pull/32521
github_commit

commit 877f017ace4b (angular/angular-cli)

Fix landed in angular/angular-cli commit 877f017ace4b — awaiting tagged release

https://github.com/angular/angular-cli/commit/877f017ace4b83277d773aa37f5813e5e9faec7e

Affected Packages

(1 across 1 ecosystem)
npm(1)
PackageVulnerable rangeFixed inDependents
@angular/ssr—19.2.21—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 7× in last 7d / 28× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

Showing the most recent 100 of 183 total refreshes for this CVE.

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Frequently asked(5)

What is CVE-2026-27738?
CVE-2026-27738 is a medium vulnerability published on February 25, 2026. The Angular SSR is a server-rise rendering tool for Angular applications. An Open Redirect vulnerability exists in the internal URL processing logic in versions on the 19.x branch prior to 19.2.21, the 20.x branch prior to 20.3.17, and the 21.x branch prior to 21.1.5 and 21.2.0-rc.1. The logic…
When was CVE-2026-27738 disclosed?
CVE-2026-27738 was first published in the National Vulnerability Database on February 25, 2026, with the most recent update on June 17, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-27738 actively exploited?
CVE-2026-27738 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0% probability of exploitation in the next 30 days, which ranks it in the top 76.9% of all scored CVEs.
What is the CVSS score of CVE-2026-27738?
CVE-2026-27738 has a CVSS v3 base score of 6.9 (NVD).
How do I remediate CVE-2026-27738?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-27738, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

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