Security readout for executives and security teams
Plain-English summary
TeleJSON before 6.0.0 can turn specially crafted JSON into JavaScript execution in a browser context. The business risk is session or data exposure in applications that parse untrusted data with this library. Evidence provided does not show known active exploitation.
Executive priority
Treat as a moderate-priority client-side security update. Prioritize internet-facing applications, authenticated portals, and products handling sensitive browser-session data. Escalate if TeleJSON parses untrusted cross-frame or third-party supplied content.
Technical view
The issue is DOM-based XSS in TeleJSON parse(). A custom reviver uses a _constructor-name_ value while recreating object prototypes and passes it to new Function() without sanitization. CVSS is 6.1 with network attack vector, low complexity, no privileges, required user interaction, and changed scope.
Likely exposure
Exposure is most likely in browser-facing applications bundling storybookjs/telejson before 6.0.0 and parsing untrusted JSON, including cross-frame communication data such as postMessage. Server-only or development-only use may have different exposure and should be verified locally.
Exploitation context
The source bundle says exploitation can occur through crafted JSON delivered to parse(), with cross-frame communication listed as an example context. KEV is false, and no cited source in the bundle confirms active exploitation in the wild.
Researcher notes
The strongest evidence is the vendor advisory plus CVE metadata and third-party descriptions. The bundle does not include proof of exploitation or broader affected product claims beyond storybookjs/telejson prior to 6.0.0.
Mitigation direction
- Upgrade TeleJSON to 6.0.0 or later where the library is used.
- Review vendor advisory guidance before relying on compensating controls.
- Avoid parsing untrusted cross-frame message data with vulnerable TeleJSON versions.
- Inventory frontend bundles and lockfiles for vulnerable TeleJSON versions.
Validation and detection
- Confirm dependency trees do not include TeleJSON versions before 6.0.0.
- Identify browser paths that call TeleJSON parse() on untrusted input.
- Review postMessage handlers and frame integrations that feed parsed JSON.
- Verify production bundles no longer include vulnerable TeleJSON code.
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-2026-47099 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
- Medium
- CVSS
- 6.1 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/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.
SSVC decision data
CVSS vector scores
2 official scoresWe 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:N/UI:R/S:C/C:L/I:L/A:N2.82.7VulnCheckCVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N——VulnCheckVulnerability scoring details
Base CVSS 4.0 score
2.1LowVector: CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:L/SA:N
Base CVSS 3.1 score
6.1MediumVector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N
Vulnerability timeline
Timeline events are normalized from CVE metadata, CNA source timelines, ADP timelines, and KEV metadata when present.
- CVE reservedCVE Program
The CVE ID was reserved by the assigning CNA.
- CVE publishedCVE Program
The CVE record was published.
- CVE updatedCVE Program
The CVE record metadata indicates this as the latest update time.
ADP provider summaries
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/storybookjs/telejson/security/advisories/GHSA-ccgf-5rwj-j3hvCVE reference, VulnCheck · vendor-advisory
- https://github.com/Niccolo10/Security-Advisories/blob/main/CVE-2026-47099/cve-2026-47099.mdCVE reference, VulnCheck · technical-description
- https://www.vulncheck.com/advisories/telejson-dom-based-xss-via-parse-functionCVE reference, VulnCheck · third-party-advisory
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.