CVE-2023-30538 - CVE House
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Status published Medium CVE-2023-30538

Stored Cross-site Scripting via improper sanitization of svg files in Discourse

Vulnerability Description

Discourse is an open source platform for community discussion. Due to the improper sanitization of SVG files, an attacker can execute arbitrary JavaScript on the users’ browsers by uploading a crafted SVG file. This issue is patched in the latest stable and tests-passed versions of Discourse. Users are advised to upgrade. For users unable to upgrade there are two possible workarounds: enable CDN handing of uploads (and ensure the CDN sanitizes SVG files) or disable SVG file uploads by ensuring that the `authorized extensions` site setting does not include `svg` (or reset that setting to the default, by default Discourse doesn't enable SVG uploads by users).

Impact Analysis

Refer to official advisory for detailed impact metrics.

Remediation

Ensure systems are updated to the latest vendor-supplied patch levels.

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Credits & Attribution

No credits recorded in the NVD database.

References

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Affected Vendor

Affected Software

discourse
Vulnerable Versions:
stable: < 3.0.3, beta: < 3.1.0.beta4

Timeline

Official Publish: April 18th, 2023
Last Modified: February 6th, 2025
Added to House: July 22nd, 2026

CVSS Vectors

V3: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N

Weaknesses (CWE)

CWE-79

MITRE ATT&CK TTPs

T1189 Drive-by Compromise
Initial Access
T1059.007 JavaScript
Execution
T1539 Steal Web Session Cookie
Collection
T1213 Data from Information Repositories
Collection
T1567 Exfiltration Over Web Service
Exfiltration
T1491.001 Defacement
Impact