CVE-2026-48821
Shaarli: DOM-based Cross-Site Scripting (XSS) in Thumbnail Synchronizer
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a DOM-based Cross-Site Scripting (XSS) vulnerability in the Thumbnail Synchronizer feature. When an administrator runs the thumbnail update process, malicious bookmark titles are returned via an AJAX response and inserted into the DOM using innerHTML without proper sanitization. The issue originates from the interaction between the backend thumbnail update endpoint and the frontend JavaScript responsible for rendering update progress. On the backend, the ThumbnailsController::ajaxUpdate method returns bookmark data formatted using the 'raw' formatter. This includes the unescaped bookmark title in the JSON response. On the client side, the script thumbnails-update.js processes this AJAX response and dynamically updates the progress interface. Administrators using the thumbnail synchronization feature are affected and exploitation could lead to session hijacking, privilege escalation, backdoor injection and full compromise. This issue has been fixed in version 0.16.2.
Attack profile
How easy it is to exploit
- Attack vector
- Local
- Complexity
- Low
- Privileges needed
- High
- User interaction
- Required
What an attacker can affect
- Confidentiality
- High
- Integrity
- High
- Availability
- None
Exploit likelihood
What each source reports
CVE List Score used
5.8
Shaarli: DOM-based Cross-Site Scripting (XSS) in Thumbnail Synchronizer
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a DOM-based Cross-Site Scripting (XSS) vulnerability in the Thumbnail Synchronizer feature. When an administrator runs the thumbnail update process, malicious bookmark titles are returned via an AJAX response and inserted into the DOM using innerHTML without proper sanitization. The issue originates from the interaction between the backend thumbnail update endpoint and the frontend JavaScript responsible for rendering update progress. On the backend, the ThumbnailsController::ajaxUpdate method returns bookmark data formatted using the 'raw' formatter. This includes the unescaped bookmark title in the JSON response. On the client side, the script thumbnails-update.js processes this AJAX response and dynamically updates the progress interface. Administrators using the thumbnail synchronization feature are affected and exploitation could lead to session hijacking, privilege escalation, backdoor injection and full compromise. This issue has been fixed in version 0.16.2.
- Record
CVE-2026-48821- CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
EUVDEUVD-2026-37796
5.8
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a DOM-based Cross-Site Scripting (XSS) vulnerability in the Thumbnail Synchronizer feature. When an administrator runs the thumbnail update process, malicious bookmark titles are returned via an AJAX response and inserted into the DOM using innerHTML without proper sanitization. The issue originates from the interaction between the backend thumbnail update endpoint and the frontend JavaScript responsible for rendering update progress. On the backend, the ThumbnailsController::ajaxUpdate method returns bookmark data formatted using the 'raw' formatter. This includes the unescaped bookmark title in the JSON response. On the client side, the script thumbnails-update.js processes this AJAX response and dynamically updates the progress interface. Administrators using the thumbnail synchronization feature are affected and exploitation could lead to session hijacking, privilege escalation, backdoor injection and full compromise. This issue has been fixed in version 0.16.2.
- Record
EUVD-2026-37796- CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
NVD
5.8
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a DOM-based Cross-Site Scripting (XSS) vulnerability in the Thumbnail Synchronizer feature. When an administrator runs the thumbnail update process, malicious bookmark titles are returned via an AJAX response and inserted into the DOM using innerHTML without proper sanitization. The issue originates from the interaction between the backend thumbnail update endpoint and the frontend JavaScript responsible for rendering update progress. On the backend, the ThumbnailsController::ajaxUpdate method returns bookmark data formatted using the 'raw' formatter. This includes the unescaped bookmark title in the JSON response. On the client side, the script thumbnails-update.js processes this AJAX response and dynamically updates the progress interface. Administrators using the thumbnail synchronization feature are affected and exploitation could lead to session hijacking, privilege escalation, backdoor injection and full compromise. This issue has been fixed in version 0.16.2.
- Record
CVE-2026-48821- CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
5.8
Shaarli: DOM-based Cross-Site Scripting (XSS) in Thumbnail Synchronizer
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a DOM-based Cross-Site Scripting (XSS) vulnerability in the Thumbnail Synchronizer feature. When an administrator runs the thumbnail update process, malicious bookmark titles are returned via an AJAX response and inserted into the DOM using innerHTML without proper sanitization. The issue originates from the interaction between the backend thumbnail update endpoint and the frontend JavaScript responsible for rendering update progress. On the backend, the ThumbnailsController::ajaxUpdate method returns bookmark data formatted using the 'raw' formatter. This includes the unescaped bookmark title in the JSON response. On the client side, the script thumbnails-update.js processes this AJAX response and dynamically updates the progress interface. Administrators using the thumbnail synchronization feature are affected and exploitation could lead to session hijacking, privilege escalation, backdoor injection and full compromise. This issue has been fixed in version 0.16.2.
- Record
CVE-2026-48821- CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSVDEBIAN-CVE-2026-48821
5.8
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a DOM-based Cross-Site Scripting (XSS) vulnerability in the Thumbnail Synchronizer feature. When an administrator runs the thumbnail update process, malicious bookmark titles are returned via an AJAX response and inserted into the DOM using innerHTML without proper sanitization. The issue originates from the interaction between the backend thumbnail update endpoint and the frontend JavaScript responsible for rendering update progress. On the backend, the ThumbnailsController::ajaxUpdate method returns bookmark data formatted using the 'raw' formatter. This includes the unescaped bookmark title in the JSON response. On the client side, the script thumbnails-update.js processes this AJAX response and dynamically updates the progress interface. Administrators using the thumbnail synchronization feature are affected and exploitation could lead to session hijacking, privilege escalation, backdoor injection and full compromise. This issue has been fixed in version 0.16.2.
- Record
DEBIAN-CVE-2026-48821- CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
OSVUBUNTU-CVE-2026-48821
5.8
Shaarli is a personal bookmarking service. Versions 0.16.1 and prior contain a DOM-based Cross-Site Scripting (XSS) vulnerability in the Thumbnail Synchronizer feature. When an administrator runs the thumbnail update process, malicious bookmark titles are returned via an AJAX response and inserted into the DOM using innerHTML without proper sanitization. The issue originates from the interaction between the backend thumbnail update endpoint and the frontend JavaScript responsible for rendering update progress. On the backend, the ThumbnailsController::ajaxUpdate method returns bookmark data formatted using the 'raw' formatter. This includes the unescaped bookmark title in the JSON response. On the client side, the script thumbnails-update.js processes this AJAX response and dynamically updates the progress interface. Administrators using the thumbnail synchronization feature are affected and exploitation could lead to session hijacking, privilege escalation, backdoor injection and full compromise. This issue has been fixed in version 0.16.2.
- Record
UBUNTU-CVE-2026-48821- CVSS 3.1
- 5.8 Medium
CVSS:3.1/AV:L/AC:L/PR:H/UI:R/S:U/C:H/I:H/A:N - Updated
- 2026-11-02
Affected products
Affected packages
| Package | Affected | Fixed |
|---|---|---|
shaarliDebian:12 |
All versions, plus listed versions 0.12.1+dfsg-80.12.1+dfsg-8+deb12u10.12.1+dfsg-8+deb12u20.13.0+dfsg-10.13.0+dfsg-2 Show 7 moreShow less0.13.0+dfsg-30.13.0+dfsg-40.13.0+dfsg-50.14.0+dfsg-10.14.0+dfsg-20.15.0+dfsg-10.16.1+dfsg-1 |
None known |
shaarliDebian:13 |
All versions, plus listed versions 0.14.0+dfsg-10.14.0+dfsg-20.14.0+dfsg-2+deb13u10.15.0+dfsg-10.16.1+dfsg-1 |
None known |
shaarliUbuntu:16.04:LTS |
All versions, plus listed versions 0.0.42~beta~dfsg1-20.0.42~beta~dfsg1-2ubuntu1 |
None known |
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | CVE List, EUVD, NVD, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.
In short
CVE-2026-48821 is a medium vulnerability (CVSS 5.8) in Shaarli, published June 17, 2026. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.13%, the 2nd percentile. No source names a fixed version.
References
github.com/shaarli/Shaarli/security/advisories/GHSA-mw63-f9qj-c5h3
github.com/shaarli/Shaarli/releases/tag/v0.16.2
github.com/CVEProject/cvelistV5/tree/main/cves/2026/48xxx/CVE-2026-48821.json
nvd.nist.gov/vuln/detail/CVE-2026-48821
security-tracker.debian.org/tracker/CVE-2026-48821
ubuntu.com/security/CVE-2026-48821
cve.org/CVERecord?id=CVE-2026-48821