CVE-2026-27122
Svelte SSR does not validate dynamic element tag names in `<svelte:element>`
Description
svelte performance oriented web framework. Prior to 5.51.5, when using <svelte:element this={tag}> in server-side rendering, the provided tag name is not validated or sanitized before being emitted into the HTML output. If the tag string contains unexpected characters, it can result in HTML injection in the SSR output. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5.
INFO
Published Date :
Feb. 20, 2026, 11:16 p.m.
Last Modified :
Feb. 20, 2026, 11:16 p.m.
Remotely Exploit :
Yes !
Source :
[email protected]
Affected Products
The following products are affected by CVE-2026-27122
vulnerability.
Even if cvefeed.io is aware of the exact versions of the
products
that
are
affected, the information is not represented in the table below.
No affected product recoded yet
CVSS Scores
| Score | Version | Severity | Vector | Exploitability Score | Impact Score | Source |
|---|---|---|---|---|---|---|
| CVSS 4.0 | MEDIUM | [email protected] |
Solution
- Update Svelte to version 5.51.5 or later.
- Validate and sanitize tag names in SSR.
- Ensure Svelte is configured securely.
Public PoC/Exploit Available at Github
CVE-2026-27122 has a 1 public
PoC/Exploit available at Github.
Go to the Public Exploits tab to see the list.
References to Advisories, Solutions, and Tools
Here, you will find a curated list of external links that provide in-depth
information, practical solutions, and valuable tools related to
CVE-2026-27122.
| URL | Resource |
|---|---|
| https://github.com/sveltejs/svelte/security/advisories/GHSA-m56q-vw4c-c2cp |
CWE - Common Weakness Enumeration
While CVE identifies
specific instances of vulnerabilities, CWE categorizes the common flaws or
weaknesses that can lead to vulnerabilities. CVE-2026-27122 is
associated with the following CWEs:
Common Attack Pattern Enumeration and Classification (CAPEC)
Common Attack Pattern Enumeration and Classification
(CAPEC)
stores attack patterns, which are descriptions of the common attributes and
approaches employed by adversaries to exploit the CVE-2026-27122
weaknesses.
We scan GitHub repositories to detect new proof-of-concept exploits. Following list is a collection of public exploits and proof-of-concepts, which have been published on GitHub (sorted by the most recently updated).
# مستودع asrar-mared هذا هو المستودع الرئيسي لمجموعة **المارد الرقمي**، نقطة التحكم المركزية التي تجمع كل المشاريع والميول التقنية تحت راية واحدة. يمثل الأساس الذي تُبنى عليه الفروع الأخرى، ويُدار منه كل شيء من تنظيم الكود إلى إدارة المجتمع. للاطلاع على المستودع: [asrar-mared](https://github.com/asrar-mared)
HTML CSS
Results are limited to the first 15 repositories due to potential performance issues.
The following list is the news that have been mention
CVE-2026-27122 vulnerability anywhere in the article.
The following table lists the changes that have been made to the
CVE-2026-27122 vulnerability over time.
Vulnerability history details can be useful for understanding the evolution of a vulnerability, and for identifying the most recent changes that may impact the vulnerability's severity, exploitability, or other characteristics.
-
New CVE Received by [email protected]
Feb. 20, 2026
Action Type Old Value New Value Added Description svelte performance oriented web framework. Prior to 5.51.5, when using <svelte:element this={tag}> in server-side rendering, the provided tag name is not validated or sanitized before being emitted into the HTML output. If the tag string contains unexpected characters, it can result in HTML injection in the SSR output. Client-side rendering is not affected. This vulnerability is fixed in 5.51.5. Added CVSS V4.0 AV:N/AC:H/AT:P/PR:H/UI:N/VC:L/VI:N/VA:N/SC:H/SI:H/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X Added CWE CWE-79 Added Reference https://github.com/sveltejs/svelte/security/advisories/GHSA-m56q-vw4c-c2cp