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CVE-2026-48821

Shaarli: DOM-based Cross-Site Scripting (XSS) in Thumbnail Synchronizer

5.8 Medium

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

0.13%Up 0.1 points since Jun 12, 2026
90%50%10%1%

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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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 MediumCVSS: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

Affected packages
PackageAffectedFixed
shaarli
Debian: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 less
0.13.0+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
shaarli
Debian: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
shaarli
Ubuntu:16.04:LTS
All versions, plus listed versions
0.0.42~beta~dfsg1-20.0.42~beta~dfsg1-2ubuntu1
None known

History

History
RecordedChangedSources
first indexedCVE 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

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