Administrator takeover via unsanitized thumbnail title insertion
Published Jun 17, 2026 · Updated Jun 17, 2026
DOM-based XSS in Shaarli 0.16.1 and earlier allows attackers to execute JavaScript when an administrator synchronizes thumbnails. ThumbnailsController::ajaxUpdate returns each bookmark title with the raw formatter, and thumbnails-update.js assigns response.title to innerHTML. An attacker-controlled bookmark title executes only when an authenticated administrator opens the thumbnail synchronization page, enabling actions in that administrator session.
Summary
What happened
DOM-based XSS in Shaarli 0.16.1 and earlier allows attackers to execute JavaScript when an administrator synchronizes thumbnails. ThumbnailsController::ajaxUpdate returns each bookmark title with the raw formatter, and thumbnails-update.js assigns response.title to innerHTML. An attacker-controlled bookmark title executes only when an authenticated administrator opens the thumbnail synchronization page, enabling actions in that administrator session.
The record
- CVE
- CVE-2026-48821
- Published
- Jun 17, 2026
- Updated
- Jun 17, 2026
- Vendor
- Shaarli
- Product
- Shaarli
- Classifications
- CWE-79, T1203
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Jun 17, 2026CVE publishedPublication date reported by the CVE source.
- Jun 17, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=< 0.16.2
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
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
- GHSA-mw63-f9qj-c5h3 reproduction stepsproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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