Medium Cross-site scripting

CVE-2026-27970 — Angular i18n vulnerable to Cross-Site Scripting (XSS)

Angular is a development platform for building mobile and desktop web applications using TypeScript/JavaScript and other languages. Versions prior to 21.2.0, 21.1.16, 20.3.17, and 19.2.19 have a cross-Site scripting vulnerability in the Angular internationalization (i18n) pipeline. In ICU messages (International Components for Unicode), HTML from translated content was not properly sanitized and could execute arbitrary JavaScript. Angular i18n typically involves three steps, extracting all messages from an application in the source language, sending the messages to be translated, and then merging their translations back into the final source code. Translations are frequently handled by contracts with specific partner companies, and involve sending the source messages to a separate contractor before receiving final translations for display to the end user. If the returned translations have malicious content, it could be rendered into the application and execute arbitrary JavaScript. When successfully exploited, this vulnerability allows for execution of attacker controlled JavaScript in the application origin. Depending on the nature of the application being exploited this could lead to credential exfiltration and/or page vandalism. Several preconditions apply to the attack. The attacker must compromise the translation file (xliff, xtb, etc.). Unlike most XSS vulnerabilities, this issue is not exploitable by arbitrary users. An attacker must first compromise an application's translation file before they can escalate privileges into the Angular application client. The victim application must use Angular i18n, use one or more ICU messages, render an ICU message, and not defend against XSS via a safe content security policy. Versions 21.2.0, 21.1.6, 20.3.17, and 19.2.19 patch the issue. Until the patch is applied, developers should consider reviewing and verifying translated content received from untrusted third parties before incorporating it in an Angular application, enabling strict CSP controls to block unauthorized JavaScript from executing on the page, and enabling Trusted Types to enforce proper HTML sanitization.

Published Feb 25, 2026 · Updated Oct 13, 2026 · Sources: NIST National Vulnerability Database, CVE Program (cve.org) e CISA ADP · CNA: GitHub_M

Low

Who exploits it and how urgent it is

A 0–100 score combining confirmed exploitation, ransomware and APT use, public exploits, EPSS and severity.

No exploitation signal in the sources consulted so far.

How the score was calculated

EPSS 0.5% (30-day exploitation probability)+6
Technical severity (medium)+3

The score orders the patch queue; it does not replace your asset context (internet exposure, criticality, compensating controls).

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the sources call it.

Exploitation

Not confirmed

Not in CISA KEV — an absence of record, not proof it is unexploited.

EPSS FIRST

0.46%

ahead of 38% of scored CVEs · Oct 14, 2026

Affects

Angular

CVSS base

6.1

Medium · 4 source(s)

Prioritization reference: 7.1 provisional

CISA SSVC assessment CISA

Three decision points CISA publishes for the CVEs it assesses (SSVC 2.0.3). A stakeholder decision, not a severity score.

Exploitation

None

none · proof-of-concept · active

Automatable

can an attacker script the kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

Fixes and mitigations documented by the sources — linked to the original advisory.

Documented patch — github.com (NIST National Vulnerability Database)
Documented patch — github.com (NIST National Vulnerability Database)
Documented patch — github.com (NIST National Vulnerability Database)
Documented patch — github.com (NIST National Vulnerability Database)
Documented patch — github.com (NIST National Vulnerability Database)

First 24 hours

Ordered from the record’s own fields — exposure first, because you cannot patch what you have not found. A rule-generated starting point.

Identify exposed assets running the affected vendor/product/version combinations (Angular Angular).
The attack is network-based and needs no privileges: restrict exposure (ACLs, VPN, WAF) until patched.
Apply the fixed version or the patch documented under Remediation.
Exploitation requires user interaction: tighten email/web filtering and warn affected users.
Search available logs for exploit probes matching the vulnerability class (cross-site scripting), errors and authentication anomalies.

Affected scope

Vendor, product and versions as the sources word them.

Vendor	Product	Versions	Status	Source
Angular	Angular	< 19.2.19≥ 20.0.0 and < 20.3.17≥ 21.0.0 and < 21.1.6version 21.2.0-next0version 21.2.0-next1version 21.2.0-next2version 21.2.0-next3version 21.2.0-rc0	Vulnerable	NIST National Vulnerability Database
Angular	Angular	version >= 21.2.0-next.0, < 21.2.0version >= 21.0.0-next.0, < 21.1.6version >= 20.0.0-next.0, < 20.3.17version >= 19.0.0-next.0, < 19.2.19version <= 18.2.14	Vulnerable	CVE Program (cve.org) e CISA ADP

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Attack vector

Network

Attack complexity

Low

Privileges required

None

User interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Every base score collected

Sources score independently and may disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Scored by
7.6	CVSS 4.0	High	—	—	security-advisories@github.com via NIST National Vulnerability Database
7.6	CVSS 4.0	High	—	—	GitHub_M via CVE Program (cve.org) e CISA ADP
7.1	CVSS 3.1	High	1.6	5.5	0b0ca135-0b70-47e7-9f44-1890c2a1c46c via NIST National Vulnerability Database
6.1	CVSS 3.1	Medium	2.8	2.7	nvd@nist.gov via NIST National Vulnerability Database

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N (score shown at the top: nvd@nist.gov)

Scoring entities (NIST, CNA, ADP) score independently; each score is shown with its origin. For prioritization we use 7.1 (0b0ca135-0b70-47e7-9f44-1890c2a1c46c via NIST National Vulnerability Database) as a conservative provisional reference — not a definitive official score.

Weakness MITRE

Weakness class according to MITRE’s CWE catalog.

CWE-79 · Cross-site Scripting (XSS)

Other CVEs with this weakness →

EPSS over time FIRST

Oct 13, 2026 → Oct 14, 2026 · 2 reading(s) · max 0.46%

Detection

Read off the CVSS vector and the weakness class. Starting points, not tested rules.

Prioritize edge telemetry for the network-reachable component (proxy, WAF, IDS/IPS).
Monitor CSP violation reports and script payloads in reflected parameters.

web/proxy/WAF logsnetwork IDS/IPSapplication logs

Timeline

What happened to this CVE, newest first.

2026
Affected products added · angular/angular
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
SSVC assessment updated
Oct 13, 2026 · CVE Program (cve.org) e CISA ADP
Record published
Oct 13, 2026
Fix documented
Oct 13, 2026 · NIST National Vulnerability Database
CVSS changed · 6.1
Oct 13, 2026 · NIST National Vulnerability Database
Source status changed · → Modified
Oct 13, 2026 · NIST National Vulnerability Database
Record created in this database
Oct 13, 2026 · NIST National Vulnerability Database
CVE published
Feb 25, 2026 · GitHub_M

Source activity

Repeated readings are counted rather than listed.

1× Official description updated · Oct 13, 2026 – Oct 13, 2026

References

8 on the record

github.com/angular/angular/commit/b85830953281ff3a1a77bbfe69019d352d509c93
Patch, x_refsource_MISC, NIST National Vulnerability Database
github.com/angular/angular/commit/306f367899dfc2e04238fecd3455547b5d54075d
Patch, x_refsource_MISC, NIST National Vulnerability Database
github.com/angular/angular/pull/67183
Issue Tracking, Patch, x_refsource_MISC, NIST National Vulnerability Database
github.com/angular/angular/commit/7d58b798c626bb0e4e5f89ca8affdce4f352b232
Patch, x_refsource_MISC, NIST National Vulnerability Database
github.com/angular/angular/security/advisories/GHSA-prjf-86w9-mfqv
Mitigation, Patch, Vendor Advisory, x_refsource_CONFIRM, NIST National Vulnerability Database
security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-27970.json
NIST National Vulnerability Database
bugzilla.redhat.com/show_bug.cgi
NIST National Vulnerability Database
access.redhat.com/security/cve/CVE-2026-27970
NIST National Vulnerability Database

Elsewhere on this site

Angular
every CVE for this vendor

Cross-site scripting
same class

CWE-79
other pages naming this weakness

Related CVEs (same products)

Medium CVE-2026-101897 Angular DevTools (Local DoS) 1d
High CVE-2026-101896 Angular: Denial of Service via Numeric URL Matrix Parameters in Server-Side Rendering (SSR) 1d
High CVE-2026-101895 Angular SSR: Denial of Service (DoS) via Infinite Loop on Malformed DOCTYPE 1d
Medium CVE-2026-88060 Angular: SSR XSS via Unescaped <template> Content Across DocumentFragment Boundaries in Fallback Raw-Content Elements Sep 10, 2026
Critical CVE-2026-88056 Angular: SSRF and Cross-Origin Credential Disclosure via URL Resolution Discrepancy in SSR Sep 10, 2026
Medium CVE-2026-88059 Angular: Information Leak via `HttpTransferCache` Bypass When Using `withRequestsMadeViaParent` Sep 10, 2026

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record

Text assembled only from the fields above — no additional claims.

What should defenders know first?

CVE-2026-27970 is "Angular i18n vulnerable to Cross-Site Scripting (XSS)", rated Medium. It affects Angular (Angular); versions are in the scope table. It is not in CISA KEV, which does not rule out exploitation. CVSS 6.1 describes technical severity. EPSS 0.46% estimates the probability of exploitation in 30 days; neither replaces your asset context. First verify whether exposed or business-critical assets run the affected versions, apply vendor fixes or mitigations, and preserve logs for review.

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