CVE-2026-4983Network attack vector

Stored XSS via unsanitized SVG extension icons

Published Jun 23, 2026 · Updated Jun 23, 2026

Stored XSS in Eclipse Open VSX before 0.34.1 allows remote authenticated users to run script via a malicious SVG extension icon. The registry stores uploaded SVG icons without sanitization and serves them as image/svg+xml without containment headers. Exploitation requires publishing access and a user visit to the icon URL; local storage exposes the application origin, while external storage limits execution to its origin.

CVSS severity4.1
Medium
EPSS probability0.31%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Stored XSS in Eclipse Open VSX before 0.34.1 allows remote authenticated users to run script via a malicious SVG extension icon. The registry stores uploaded SVG icons without sanitization and serves them as image/svg+xml without containment headers. Exploitation requires publishing access and a user visit to the icon URL; local storage exposes the application origin, while external storage limits execution to its origin.

The record

CVE
CVE-2026-4983
Published
Jun 23, 2026
Updated
Jun 23, 2026
Vendor
The Eclipse Foundation
Product
Eclipse Open VSX
Classifications
CWE-79, T1204.001
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Jun 23, 2026CVE publishedPublication date reported by the CVE source.
  2. Jun 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=0.1.0 <0.34.1

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

The Eclipse Foundation · Eclipse Open VSXversion=0.1.0 <0.34.1

Published CVSS scores

5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/I:L/A:N
4.1Eclipse FoundationCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:N/I:L/A:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1204.001Malicious Link

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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