Stored XSS via unsanitized image filename
Published Jan 2, 2026 · Updated Jan 2, 2026
Stored XSS in emlog 2.5.23 allows remote authenticated users to execute script in an administrator's browser via an image filename. The Resource media library stores an uploaded image name and renders it without neutralizing HTML event-handler markup when the name is hovered. Any account that can publish an article can plant the filename, but execution requires an administrator to open the media library and hover over the image name, exposing the administrator's session cookie.
Summary
What happened
Stored XSS in emlog 2.5.23 allows remote authenticated users to execute script in an administrator's browser via an image filename. The Resource media library stores an uploaded image name and renders it without neutralizing HTML event-handler markup when the name is hovered. Any account that can publish an article can plant the filename, but execution requires an administrator to open the media library and hover over the image name, exposing the administrator's session cookie.
The record
- CVE
- CVE-2026-21431
- Published
- Jan 2, 2026
- Updated
- Jan 2, 2026
- Vendor
- emlog
- Product
- emlog
- Classifications
- CWE-79, T1539
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Jan 2, 2026CVE publishedPublication date reported by the CVE source.
- Jan 2, 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.
- Affected versionversion== 2.5.23
What conditions does exploitation require?
What is affected?
Published CVSS scores
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.
Weakness, pattern, technique
Public exploit references
- GHSA-9vc2-crhr-248x filename payload and video PoCproof of concept · demonstrated
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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