Stored XSS via denylist-bypassing HTML upload
Published Mar 15, 2022 · Updated Aug 2, 2024
Stored cross-site scripting in ShowDoc before 2.10.4 allows remote authenticated users to run script in another user's browser via an uploaded HTML file. The attachment and image upload handlers pass filenames to a denylist-based isDangerFilename check, which permits compound extensions ending in .html; the patched code replaces that check with a fixed extension allowlist. An account with upload access and a victim who opens the stored file are required, bounding impact to the victim's browser session.
Summary
What happened
Stored cross-site scripting in ShowDoc before 2.10.4 allows remote authenticated users to run script in another user's browser via an uploaded HTML file. The attachment and image upload handlers pass filenames to a denylist-based isDangerFilename check, which permits compound extensions ending in .html; the patched code replaces that check with a fixed extension allowlist. An account with upload access and a victim who opens the stored file are required, bounding impact to the victim's browser session.
The record
- CVE
- CVE-2022-0950
- Published
- Mar 15, 2022
- Updated
- Aug 2, 2024
- Vendor
- ShowDoc
- Product
- ShowDoc
- Classifications
- CWE-79, CWE-434, T1203
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Mar 15, 2022CVE publishedPublication date reported by the CVE source.
- Aug 2, 2024Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=unspecified <2.10.4
What conditions does exploitation require?
What is affected?
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- huntr HTML-upload exploit reportproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo