6.8

CVE-2026-27125: Svelte SSR attribute spreading includes inherited properties from prototype chain

Analyzed
AliasesCGA-pv83-rmrj-cvg3CGA-qfj4-xfw6-jqw5GHSA-crpf-4hrx-3jrp
Published 20-02-2026Last modified 25-02-2026

Vulnerability summary

CVE-2026-27125 is a medium (CVSS 6.8) vulnerability in svelte. EPSS estimates a 0.43% chance of exploitation in the next 30 days, higher than 37.7% of scored vulnerabilities.

Priority
Routine

Not severe (CVSS 5.3, network access); no exploitation reported by the 5 checked sources

Source freshness unavailable

How is this decided?
CVSS score
6.8/10
010
Medium · v3.1 (NVD)
EPSS score
0.43%
0%100%
Low · -0.06 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-FCQR-R83P-Q47H

Timeline

  1. 20-02-2026
    PublishedVulnerability first disclosed.
  2. 25-02-2026
    Last modifiedVulnerability information updated.

Description

svelte performance oriented web framework. Prior to 5.51.5, in server-side rendering, attribute spreading on elements (e.g. <div {...attrs}>) enumerates inherited properties from the object's prototype chain rather than only own properties. In environments where Object.prototype has already been polluted — a precondition outside of Svelte's control — this can cause unexpected attributes to appear in SSR output or cause SSR to throw errors. 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

0.43%

Chance of exploitation in the next 30 days

Percentile

38%

Versus all other CVEs

30-day change

Decrease -0.06 pp

From 0.50% 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, low-privilege 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

6 links