# CVE-2026-91772

## Summary

- **CVE ID:** CVE-2026-91772
- **Severity:** MEDIUM
- **CVSS Score:** 6.1 (CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:P/VC:L/VI:L/VA:N/SC:L/SI:L/SA:N)
- **CWE:** CWE-601
- **Published:** Sep 15, 2026
- **Last Modified:** Sep 16, 2026

## Description

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.

## Affected Products

- halo-dev — halo (0)

## References

- [CNA](https://github.com/halo-dev/halo/issues/10247)
- [CNA](https://github.com/halo-dev/halo/blob/v2.26.1/application/src/main/java/run/halo/app/core/endpoint/theme/ThumbnailEndpoint.java#L76-L98)
- [CNA](https://github.com/halo-dev/halo/blob/v2.26.1/application/src/main/resources/extensions/role-template-anonymous.yaml#L53-L55)
- [CNA](https://github.com/halo-dev/halo)
- [CNA](https://www.vulncheck.com/advisories/halo-through-2.26.1-open-redirect-via-unvalidated-uri-parameter)

## Exploitation Prediction (EPSS)

- **EPSS Score:** 0.18%
- **EPSS Percentile:** 8.2

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_Exported from OnDuty AI Vulnerability Intelligence on 2026-09-18._