Phishing redirects via unvalidated thumbnail URI
Published Sep 15, 2026 · Updated Sep 15, 2026
Open redirect in Halo 2.26.1 and earlier allows remote attackers to send visitors to external sites through an anonymous thumbnail request. ThumbnailEndpoint.getThumbnailByUri passes the raw uri parameter to DefaultThumbnailService.get and redirects to the original value when no attachment matches. No authentication is required, but a visitor must follow a crafted Halo link; the trusted-domain redirect enables phishing and redirect-trust abuse.
Summary
What happened
Open redirect in Halo 2.26.1 and earlier allows remote attackers to send visitors to external sites through an anonymous thumbnail request. ThumbnailEndpoint.getThumbnailByUri passes the raw uri parameter to DefaultThumbnailService.get and redirects to the original value when no attachment matches. No authentication is required, but a visitor must follow a crafted Halo link; the trusted-domain redirect enables phishing and redirect-trust abuse.
The record
- CVE
- CVE-2026-91772
- Published
- Sep 15, 2026
- Updated
- Sep 15, 2026
- Vendor
- Halo
- Product
- Halo
- Classifications
- T1566.002
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Sep 15, 2026CVE publishedPublication date reported by the CVE source.
- Sep 15, 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=0 <=2.26.1
What conditions does exploitation require?
What is affected?
Published CVSS scores
No CVSS assessment is available in this record.
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
- Thumbnail via-uri open redirect proof of conceptproof 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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