Security readout for executives and security teams
Plain-English summary
This issue affects older Scratch Addons browser extensions. A flaw in the More Links addon could turn escaped page content back into executable script when a victim visited a specific site. The main business action is to ensure Scratch Addons is updated to 1.3.2 or later, or disable More Links where updating is not possible.
Executive priority
Prioritize remediation for managed browsers that allow Scratch Addons. The fix is straightforward, and current exposure should be low where browser auto-update is working. Organizations with extension pinning or unmanaged browsers should validate quickly.
Technical view
Scratch Addons before 1.3.2 has DOM-based XSS in the More Links addon. An incorrect regular expression could unescape HTML-escaped values, enabling script execution in the extension context after user interaction. CVSS 3.1 is 7.6 with scope changed, low confidentiality impact, high integrity impact, and no availability impact.
Likely exposure
Exposure is limited to users running Scratch Addons versions earlier than 1.3.2, especially where browser extension auto-updates were disabled, delayed, or centrally pinned. The vulnerable component is the More Links addon, which can also be disabled through the extension options.
Exploitation context
The source bundle does not show KEV listing or public evidence of active exploitation. Exploitation requires user interaction and visiting a specific website. Treat it as a real browser-extension XSS risk, but do not assume in-the-wild exploitation from the provided evidence.
Researcher notes
The affected product is ScratchAddons <1.3.2. The vulnerability is CWE-79 DOM XSS in addons/more-links/userscript.js. The provided evidence identifies the fix commit and v1.3.2 release, but not exploit-in-the-wild activity, affected CPEs, or additional impacted products.
Mitigation direction
- Update Scratch Addons to version 1.3.2 or later.
- Confirm browser extension auto-update is enabled and functioning.
- Disable the More Links addon if immediate updating is not possible.
- Check the GitHub advisory and release notes for vendor guidance.
Validation and detection
- Inventory installed Scratch Addons versions across managed browsers.
- Verify no users remain on Scratch Addons below 1.3.2.
- Check whether the More Links addon is enabled on vulnerable installations.
- Review extension management policy for pinned or blocked updates.
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-2020-26239 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
- High
- CVSS
- 7.6 (3.1)
- Known Exploited
- No
- Published
Vector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/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:C/C:L/I:H/A:N2.34.7Primary CVE scoreVulnerability scoring details
Base CVSS 3.1 score
7.6HighVector: CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/A:N
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/ScratchAddons/ScratchAddons/security/advisories/GHSA-6qfq-px3r-xj4pCVE reference · x_refsource_CONFIRM
- https://github.com/ScratchAddons/ScratchAddons/commit/b9a52d6532c8514254c7cc1d8e18710dbedc41ffCVE reference · x_refsource_MISC
- https://github.com/ScratchAddons/ScratchAddons/blob/a471893df403f86c9182970678175d4772a0690c/addons/more-links/userscript.js#L15CVE reference · x_refsource_MISC
- https://github.com/ScratchAddons/ScratchAddons/releases/tag/v1.3.2CVE 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.