6.1Medium
CVE-2026-91772
Halo through 2.26.1 contains an open redirect vulnerability in the anonymous thumbnail endpoint that fails to validate the uri query parameter. Attackers can craft malicious links on the trusted Halo domain that redirect visitors to arbitrary external sites, enabling phishing attacks and abuse of redirect-based trust relationships.
What this means for your business
- An attacker can use it remotely, over a network, without a login, but only after tricking someone into an action such as opening a file or a link.
- FIRST's prediction model gives it a 0.2% chance of attack attempts being seen in the next 30 days, ranking above 8% of all known flaws.
What to do
- 1Ask your IT team or provider whether any of your systems use the affected product.
- 2If you do, follow the vendor's guidance. No patch reference has been published yet.
Not sure if your company is exposed?
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Scoring
- CVSS
- 6.1 (v3.1)
- Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N- CVSS v4
- 5.3
- Weakness
- CWE-601
- Assigned by
- disclosure@vulncheck.com
Dates
- Published
- 2026-09-15
- Last modified
- 2026-09-16
- Sources
- NVD
References
- https://github.com/halo-dev/halo
- https://github.com/halo-dev/halo/blob/v2.26.1/application/src/main/java/run/halo/app/core/endpoint/theme/ThumbnailEndpoint.java#L76-L98
- https://github.com/halo-dev/halo/blob/v2.26.1/application/src/main/resources/extensions/role-template-anonymous.yaml#L53-L55
- https://github.com/halo-dev/halo/issues/10247
- https://www.vulncheck.com/advisories/halo-through-2.26.1-open-redirect-via-unvalidated-uri-parameter