5.4

CVE-2026-27122: Svelte SSR does not validate dynamic element tag names in `<svelte:element>`

Analyzed
AliasesCGA-gvg9-mr28-94gmCGA-hr6f-qq9h-r524GHSA-m56q-vw4c-c2cp
Published 20-02-2026Last modified 23-02-2026

Vulnerability summary

CVE-2026-27122 is a medium (CVSS 5.4) vulnerability in svelte. EPSS estimates a 0.22% chance of exploitation in the next 30 days, higher than 12.6% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.1, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
5.4/10
010
Medium · v3.1 (NVD)
EPSS score
0.22%
0%100%
Low · 0.00 pp in 30 days
KEVNot listedNot listed by any tracked catalog.
RansomwareNot flaggedNo ransomware use recorded.
Public exploits0No public exploits recorded

Advisory lineage

Upstream 0 · Downstream 0 · Related 1
CGA-246G-Q6QF-FPMV

Timeline

  1. 20-02-2026
    PublishedVulnerability first disclosed.
  2. 23-02-2026
    Last modifiedVulnerability information updated.

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.

CVSS metrics

6 scores · 5 sources · 2 versions

EPSS trend

Probability

0.22%

Chance of exploitation in the next 30 days

Percentile

13%

Versus all other CVEs

30-day change

No change 0.00 pp

From 0.22% on 04-10-2026

04-10-202603-11-2026

Known exploited

Compare KEV catalogs
CISA KEV

Not in the CISA KEV catalog.

ENISA CNW

Not in the ENISA CNW catalog.

CIRCL

Not in the CIRCL catalog.

Public exploits

0 found

No public exploits indexed.

Weaknesses

CWE · root cause

Affected systems

Version check

Known conditions: network-reachable, administrative account, no user interaction (CVSS vector). Other conditions: not stated in public data.

Chainguard5 products
  • langfuse-2-workerAll versions (No fix recorded)
  • langfuse-3-worker< 3.163.0-r0
  • langfuse-fips-2-workerAll versions (No fix recorded)
  • langfuse-fips-3-worker< 3.163.0-r0
  • langfuse-fips-3.152-workerAll versions (No fix recorded)
Npm1 product
  • svelte< 5.51.5
Svelte1 product
Sveltejs1 product
Wolfi1 product
  • langfuse-3-worker< 3.163.0-r0

5 vendors · 9 products

References

4 links