How severe is CVE-2026-27901?

No CVSS score has been assigned to CVE-2026-27901 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-27901?

CVE-2026-27901 affects the following packages: svelte (npm). Ecosystems affected: npm.

How do I fix CVE-2026-27901?

Update svelte to 5.53.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27901 is resolved across your whole dependency graph.

How do I detect CVE-2026-27901 in my npm dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for svelte. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.

How do I mitigate CVE-2026-27901 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2026-27901?

O3 pinpoints whether CVE-2026-27901 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Is CVE-2026-27901 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-27901 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What type of vulnerability is CVE-2026-27901?

CVE-2026-27901 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

When was CVE-2026-27901 published, and has it been updated?

CVE-2026-27901 was published on February 26, 2026 and was last updated on July 15, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

📦 npm

CVE-2026-27901

Fix: sveltejs/svelte@0df5abc

CVE-2026-27901 is a Cross-site Scripting (XSS) vulnerability in svelte. O3 Security confirms whether CVE-2026-27901 is actually reachable in your code before you act, and blocks exploitation at runtime until you patch.

Svelte vulnerable to XSS during SSR with contenteditable `bind:innerText` and `bind:textContent`

Also known asGHSA-phwv-c562-gvmh

Published

Feb 26, 2026

Updated

Jul 15, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Real-World Exposure

1 pkg affected

How broadly this vulnerability is actually deployed: weekly install volume shows current usage, a proxy for how much of the ecosystem is exposed.

sveltenpm

5.4Mdownloads / week

Description

Svelte performance oriented web framework. Prior to version 5.53.5, the contents of bind:innerText and bind:textContent on contenteditable elements were not properly escaped. This could enable HTML injection and Cross-Site Scripting (XSS) if rendering untrusted data as the binding's initial value on the server. Version 5.53.5 fixes the issue.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
📦npm	`svelte`	all versions	5.53.5

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for svelte. O3's reachability analysis confirms whether the vulnerable code path is actually invoked in your application, so you act on real exposure instead of every transitive match.
Fix
Update svelte to 5.53.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-27901 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 pinpoints whether CVE-2026-27901 is reachable in your code and exactly where to fix it, then blocks exploitation in production at runtime until the patched version is deployed.

Tailored to CVE-2026-27901. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

Svelte performance oriented web framework. Prior to version 5.53.5, the contents of `bind:innerText` and `bind:textContent` on `contenteditable` elements were not properly escaped. This could enable HTML injection and Cross-Site Scripting (XSS) if rendering untrusted data as the binding's initial value on the server. Version 5.53.5 fixes the issue.

O3 Security · Impact-Aware SCA

Is CVE-2026-27901 in your dependencies?

O3 detects CVE-2026-27901 across npm dependencies and uses function-level reachability to confirm whether the vulnerable code path is actually reachable — not just present. No false positives.

Scan my dependencies How O3 SCA works