CVE-2023-30538Network attack vector

Stored XSS via unsanitized SVG uploads

Published Apr 18, 2023 · Updated Feb 6, 2025

Stored XSS in SVG uploads in Discourse stable before 3.0.3 and beta or tests-passed before 3.1.0.beta4 allows remote attackers to execute JavaScript. The SVG upload sanitizer stores attacker-controlled files without neutralizing embedded script, which executes when a user opens the uploaded image. Exploitation requires user interaction and a site that permits SVG uploads, a non-default setting; execution remains in the viewing user's browser context.

CVSS severity3.1
Low
EPSS probability0.36%
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 SVG uploads in Discourse stable before 3.0.3 and beta or tests-passed before 3.1.0.beta4 allows remote attackers to execute JavaScript. The SVG upload sanitizer stores attacker-controlled files without neutralizing embedded script, which executes when a user opens the uploaded image. Exploitation requires user interaction and a site that permits SVG uploads, a non-default setting; execution remains in the viewing user's browser context.

The record

CVE
CVE-2023-30538
Published
Apr 18, 2023
Updated
Feb 6, 2025
Vendor
Discourse
Product
Discourse
Classifications
CWE-79, T1189
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Apr 18, 2023CVE publishedPublication date reported by the CVE source.
  2. Feb 6, 2025Record 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=beta: < 3.1.0.beta4
  2. Affected versionversion=stable: < 3.0.3

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Discourse · Discourseversion=beta: < 3.1.0.beta4; version=stable: < 3.0.3

Published CVSS scores

5.4GitHub, Inc. CNACVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
3.1Discourse GitHub Security AdvisoryCVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:L/I:N/A:N
5.4NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:C/C:L/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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-79Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
T1189Drive-by Compromise

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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