Security readout for executives and security teams
Plain-English summary
This is a low-severity cross-site scripting issue in Angular’s comment handling. An attacker could remotely affect page integrity, but the CVSS data indicates they need low privileges and user interaction. The source bundle names fixed versions, and it does not show active exploitation.
Executive priority
Treat this as a routine patching item, not an emergency, unless affected Angular apps handle sensitive workflows or broad authenticated user content. Fixed versions are available, so remediation should be folded into normal dependency maintenance.
Technical view
CVE-2021-4231 is CWE-79 affecting Angular 11.0.0-11.0.4 and 11.1.0-next.0-next.2. The reported flaw is comment handling that can lead to XSS. CVSS 3.1 is 3.5 with network attack vector, low complexity, low privileges, required user interaction, and low integrity impact only.
Likely exposure
Exposure is most likely in web applications still running the listed Angular 11 releases, especially where attacker-controlled content can reach comment-handling paths. The bundle does not identify affected configurations beyond those versions.
Exploitation context
The bundle says remote attack is possible and may require authentication first. It provides no evidence of public weaponization, no proof-of-concept details, and KEV is false, so active exploitation should not be assumed.
Researcher notes
The source detail is limited to version ranges, CVSS, CWE-79 classification, comment handling, and the patch reference. Avoid assuming a specific exploitable sink or bypass without reviewing the Angular issue and patch context.
Mitigation direction
- Upgrade Angular 11.0.x applications to 11.0.5 or later.
- Upgrade Angular 11.1.0-next applications to 11.1.0-next.3 or later.
- Confirm dependency lockfiles no longer resolve to affected Angular versions.
- Check Angular vendor guidance before applying compensating controls not named in sources.
Validation and detection
- Inventory applications for Angular 11.0.0 through 11.0.4.
- Check for Angular 11.1.0-next.0 through 11.1.0-next.2.
- Verify builds include the patch commit or a fixed release.
- Run regression tests covering rendering of untrusted content.
- Review authenticated user paths that accept or display user-controlled content.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-79: User-session and phishing behavior lookup
Client-side and session-facing weaknesses should be reviewed alongside initial-access and user-execution behaviors. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCVE-2021-4231 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Low
- CVSS
- 3.5 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N2.11.4Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
3.5LowVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:L/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/angular/angular/issues/40136CVE reference · x_refsource_MISC
- https://github.com/angular/angular/commit/ba8da742e3b243e8f43d4c63aa842b44e14f2b09CVE reference · x_refsource_MISC
- https://security.snyk.io/vuln/SNYK-JS-ANGULARCORE-1070902CVE reference · x_refsource_MISC
- https://vuldb.com/?id.181356CVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.