GHSA-97r8-rf7q-wmjw
Sveltia CMS: Stored XSS in entry summary rendering via entity-decoded HTML
GHSA-97r8-rf7q-wmjw is a low vulnerability (CVSS 2.3) in @sveltia/cms, published May 18, 2026. No source lists public exploit code. Fixed in @sveltia/cms 0.160.0.
- Severity
- 2.3 LowCVSS 4.0, GitHub Advisories
- Exploit chance
- UnscoredNo EPSS score yet
- Exploitation
- None knownNot on CISA’s or ENISA’s lists
- Fixed in
0.160.0@sveltia/cms +1 more
Description
Impact
A stored cross-site scripting (XSS) vulnerability affected entry summary rendering in Sveltia CMS.
Entry summaries that allowed limited Markdown were parsed, sanitized, and then HTML entities were decoded. This order allowed specially crafted entity-encoded HTML, such as encoded tags or event handler attributes, to become active HTML after sanitization. When the resulting summary was rendered in the CMS UI, arbitrary JavaScript could execute in the browser of a user viewing the affected entry list or search result.
The practical impact is limited in currently supported Sveltia CMS usage because the CMS is intended for a single developer or a small trusted team, and open authoring / untrusted multi-user authoring is not currently implemented. Exploitation requires the ability to place malicious content into the repository or content source that the CMS loads.
Patches
The issue has been patched by changing entry summary sanitization so that HTML entity decoding happens before sanitization for Markdown-enabled summaries. This ensures any decoded HTML is processed by the sanitizer before being rendered.
Users should upgrade to Sveltia CMS v0.160.1 or later.
Workarounds
If upgrading is not immediately possible, avoid loading CMS content from untrusted authors and review content for entity-encoded HTML payloads in fields used by entry summaries.
Administrators can also reduce exposure by avoiding Markdown-enabled summary rendering for untrusted content where possible, or by ensuring repository write access is limited to trusted users only.
Resources
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- https://cwe.mitre.org/data/definitions/79.html
Attack profile
How easy it is to exploit
- Attack vector
- Network
- Complexity
- Low
- Privileges needed
- None
- User interaction
- Passive
What an attacker can affect
- Confidentiality
- None
- Integrity
- Low
- Availability
- None
Affected packages
| Package | Affected | Fixed |
|---|---|---|
@sveltia/cmsnpm | before 0.160.0 | 0.160.0 |
@sveltia/cmsnpm | before 0.160.1 | 0.160.1 |
What each source reports
GitHub Advisories Score used
Sveltia CMS: Stored XSS in entry summary rendering via entity-decoded HTML
Impact
A stored cross-site scripting (XSS) vulnerability affected entry summary rendering in Sveltia CMS.
Entry summaries that allowed limited Markdown were parsed, sanitized, and then HTML entities were decoded. This order allowed specially crafted entity-encoded HTML, such as encoded tags or event handler attributes, to become active HTML after sanitization. When the resulting summary was rendered in the CMS UI, arbitrary JavaScript could execute in the browser of a user viewing the affected entry list or search result.
The practical impact is limited in currently supported Sveltia CMS usage because the CMS is intended for a single developer or a small trusted team, and open authoring / untrusted multi-user authoring is not currently implemented. Exploitation requires the ability to place malicious content into the repository or content source that the CMS loads.
Patches
The issue has been patched by changing entry summary sanitization so that HTML entity decoding happens before sanitization for Markdown-enabled summaries. This ensures any decoded HTML is processed by the sanitizer before being rendered.
Users should upgrade to Sveltia CMS v0.160.1 or later.
Workarounds
If upgrading is not immediately possible, avoid loading CMS content from untrusted authors and review content for entity-encoded HTML payloads in fields used by entry summaries.
Administrators can also reduce exposure by avoiding Markdown-enabled summary rendering for untrusted content where possible, or by ensuring repository write access is limited to trusted users only.
Resources
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- https://cwe.mitre.org/data/definitions/79.html
- Record
GHSA-97r8-rf7q-wmjw- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-79
- Updated
- 2026-11-02
OSV
Sveltia CMS: Stored XSS in entry summary rendering via entity-decoded HTML
Impact
A stored cross-site scripting (XSS) vulnerability affected entry summary rendering in Sveltia CMS.
Entry summaries that allowed limited Markdown were parsed, sanitized, and then HTML entities were decoded. This order allowed specially crafted entity-encoded HTML, such as encoded tags or event handler attributes, to become active HTML after sanitization. When the resulting summary was rendered in the CMS UI, arbitrary JavaScript could execute in the browser of a user viewing the affected entry list or search result.
The practical impact is limited in currently supported Sveltia CMS usage because the CMS is intended for a single developer or a small trusted team, and open authoring / untrusted multi-user authoring is not currently implemented. Exploitation requires the ability to place malicious content into the repository or content source that the CMS loads.
Patches
The issue has been patched by changing entry summary sanitization so that HTML entity decoding happens before sanitization for Markdown-enabled summaries. This ensures any decoded HTML is processed by the sanitizer before being rendered.
Users should upgrade to Sveltia CMS v0.160.1 or later.
Workarounds
If upgrading is not immediately possible, avoid loading CMS content from untrusted authors and review content for entity-encoded HTML payloads in fields used by entry summaries.
Administrators can also reduce exposure by avoiding Markdown-enabled summary rendering for untrusted content where possible, or by ensuring repository write access is limited to trusted users only.
Resources
- CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
- https://cwe.mitre.org/data/definitions/79.html
- Record
GHSA-97r8-rf7q-wmjw- CVSS 4.0
- 2.3 Low
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:P/VC:N/VI:L/VA:N/SC:N/SI:N/SA:N - Weakness
- CWE-79
- Updated
- 2026-11-02
History
| Recorded | Changed | Sources |
|---|---|---|
| first indexed | GitHub Advisories, OSV |
Dates are when Every CVE recorded each change. Upstream dates may differ.