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GitHub_MCVELIST:CVE-2020-26239

HistoryNov 23, 2020 - 7:05 p.m.

CVE-2020-26239 Cross-Site Scripting in Scratch browser addons

2020-11-2319:05:15

CWE-79

GitHub_M

www.cve.org

7.6 High

CVSS3

Attack Vector

NETWORK

Attack Complexity

LOW

Privileges Required

LOW

User Interaction

REQUIRED

Scope

CHANGED

Confidentiality Impact

LOW

Integrity Impact

HIGH

Availability Impact

NONE

CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:H/A:N

0.001 Low

EPSS

Percentile

31.7%

JSON

Scratch Addons is a WebExtension that supports both Chrome and Firefox. Scratch Addons before version 1.3.2 is vulnerable to DOM-based XSS. If the victim visited a specific website, the More Links addon of the Scratch Addons extension used incorrect regular expression which caused the HTML-escaped values to be unescaped, leading to XSS. Scratch Addons version 1.3.2 fixes the bug. The extension will be automatically updated by the browser. More Links addon can be disabled via the option of the extension.

CNA Affected

[
  {
    "product": "ScratchAddons",
    "vendor": "ScratchAddons",
    "versions": [
      {
        "status": "affected",
        "version": "< 1.3.2"
      }
    ]
  }
]

References

github.com/ScratchAddons/ScratchAddons/blob/a471893df403f86c9182970678175d4772a0690c/addons/more-links/userscript.js#L15

github.com/ScratchAddons/ScratchAddons/commit/b9a52d6532c8514254c7cc1d8e18710dbedc41ff

github.com/ScratchAddons/ScratchAddons/releases/tag/v1.3.2

github.com/ScratchAddons/ScratchAddons/security/advisories/GHSA-6qfq-px3r-xj4p