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fix(deps): update dependency postcss to v8.5.10 [security] - autoclosed#4598

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fix(deps): update dependency postcss to v8.5.10 [security] - autoclosed#4598
renovate[bot] wants to merge 1 commit into
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chore/renovate/npm-postcss-vulnerability

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@renovate renovate Bot commented Apr 27, 2026

This PR contains the following updates:

Package Change Age Confidence
postcss (source) 8.5.88.5.10 age confidence

PostCSS has XSS via Unescaped </style> in its CSS Stringify Output

CVE-2026-41305 / GHSA-qx2v-qp2m-jg93

More information

Details

PostCSS: XSS via Unescaped </style> in CSS Stringify Output
Summary

PostCSS v8.5.5 (latest) does not escape </style> sequences when stringifying CSS ASTs. When user-submitted CSS is parsed and re-stringified for embedding in HTML <style> tags, </style> in CSS values breaks out of the style context, enabling XSS.

Proof of Concept
const postcss = require('postcss');

// Parse user CSS and re-stringify for page embedding
const userCSS = 'body { content: "</style><script>alert(1)</script><style>"; }';
const ast = postcss.parse(userCSS);
const output = ast.toResult().css;
const html = `<style>${output}</style>`;

console.log(html);
// <style>body { content: "</style><script>alert(1)</script><style>"; }</style>
//
// Browser: </style> closes the style tag, <script> executes

Tested output (Node.js v22, postcss v8.5.5):

Input: body { content: "</style><script>alert(1)</script><style>"; }
Output: body { content: "</style><script>alert(1)</script><style>"; }
Contains </style>: true
Impact

Impact non-bundler use cases since bundlers for XSS on their own. Requires some PostCSS plugin to have malware code, which can inject XSS to website.

Suggested Fix

Escape </style in all stringified output values:

output = output.replace(/<\/(style)/gi, '<\\/$1');
Credits

Discovered and reported by Sunil Kumar (@​TharVid)

Severity

  • CVSS Score: 6.1 / 10 (Medium)
  • Vector String: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

References

This data is provided by the GitHub Advisory Database (CC-BY 4.0).


Release Notes

postcss/postcss (postcss)

v8.5.10

Compare Source

  • Fixed XSS via unescaped </style> in non-bundler cases (by @​TharVid).

v8.5.9

Compare Source

  • Speed up source map encoding paring in case of the error.

Configuration

📅 Schedule: (in timezone America/Los_Angeles)

  • Branch creation
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  • Automerge
    • At any time (no schedule defined)

🚦 Automerge: Disabled by config. Please merge this manually once you are satisfied.

Rebasing: Whenever PR is behind base branch, or you tick the rebase/retry checkbox.

🔕 Ignore: Close this PR and you won't be reminded about this update again.


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This PR was generated by Mend Renovate. View the repository job log.

@renovate renovate Bot added the security Security related label Apr 27, 2026
@renovate renovate Bot requested a review from a team as a code owner April 27, 2026 07:34
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renovate Bot commented Apr 27, 2026

⚠️ Artifact update problem

Renovate failed to update an artifact related to this branch. You probably do not want to merge this PR as-is.

♻ Renovate will retry this branch, including artifacts, only when one of the following happens:

  • any of the package files in this branch needs updating, or
  • the branch becomes conflicted, or
  • you click the rebase/retry checkbox if found above, or
  • you rename this PR's title to start with "rebase!" to trigger it manually

The artifact failure details are included below:

File name: pnpm-lock.yaml
Scope: all 97 workspace projects
Progress: resolved 1, reused 0, downloaded 0, added 0
examples/ui-prompting-examples           |  WARN  deprecated @types/uuid@11.0.0
Progress: resolved 39, reused 0, downloaded 0, added 0
Progress: resolved 61, reused 0, downloaded 0, added 0
Progress: resolved 114, reused 0, downloaded 0, added 0
/tmp/renovate/repos/github/SAP/open-ux-tools/packages/backend-proxy-middleware-cf:
 ERR_PNPM_UNSUPPORTED_ENGINE  Unsupported environment (bad pnpm and/or Node.js version)

This error happened while installing a direct dependency of /tmp/renovate/repos/github/SAP/open-ux-tools/packages/backend-proxy-middleware-cf

Your Node version is incompatible with "@sap/approuter@20.10.0".

Expected version: ^20.0.0 || ^22.0.0
Got: v24.15.0

This is happening because the package's manifest has an engines.node field specified.
To fix this issue, install the required Node version.

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changeset-bot Bot commented Apr 27, 2026

⚠️ No Changeset found

Latest commit: dd2f2fa

Merging this PR will not cause a version bump for any packages. If these changes should not result in a new version, you're good to go. If these changes should result in a version bump, you need to add a changeset.

This PR includes no changesets

When changesets are added to this PR, you'll see the packages that this PR includes changesets for and the associated semver types

Click here to learn what changesets are, and how to add one.

Click here if you're a maintainer who wants to add a changeset to this PR

@renovate renovate Bot force-pushed the chore/renovate/npm-postcss-vulnerability branch 2 times, most recently from b058af8 to 8d59219 Compare April 27, 2026 15:55
@renovate renovate Bot changed the title fix(deps): update dependency postcss to v8.5.10 [security] fix(deps): update dependency postcss to v8.5.10 [security] - autoclosed Apr 27, 2026
@renovate renovate Bot closed this Apr 27, 2026
@renovate renovate Bot deleted the chore/renovate/npm-postcss-vulnerability branch April 27, 2026 18:22
@renovate renovate Bot changed the title fix(deps): update dependency postcss to v8.5.10 [security] - autoclosed fix(deps): update dependency postcss to v8.5.10 [security] Apr 27, 2026
@renovate renovate Bot reopened this Apr 27, 2026
@renovate renovate Bot force-pushed the chore/renovate/npm-postcss-vulnerability branch 19 times, most recently from 1d2c494 to 0805e0c Compare April 30, 2026 15:40
@renovate renovate Bot force-pushed the chore/renovate/npm-postcss-vulnerability branch 9 times, most recently from c508193 to 0deec98 Compare May 6, 2026 13:57
@renovate renovate Bot force-pushed the chore/renovate/npm-postcss-vulnerability branch from 0deec98 to dd2f2fa Compare May 6, 2026 14:05
@renovate renovate Bot changed the title fix(deps): update dependency postcss to v8.5.10 [security] fix(deps): update dependency postcss to v8.5.10 [security] - autoclosed May 6, 2026
@renovate renovate Bot closed this May 6, 2026
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