CVE-2025-51857
MediumCVSS 6.1Exploitation Probability (EPSS)
Low risk13th percentile - higher than 13% of all known CVEs
Summary
An XSS vulnerability in the reconcile method of the AttachmentReconciler class in Halo system v.2.20.18LTS and earlier allows an attacker to inject malicious scripts.
Risk Assessment
An attacker can exploit this vulnerability to steal user sessions, take over accounts, or perform unauthorized actions in the victim's context.
Recommendation
Immediately update Halo system to a version newer than 2.20.18LTS and apply input filtering and output encoding in the reconcile method.
Other vulnerabilities in Halo
See all- CVE-2026-97182High
A security vulnerability has been detected in halo-dev Halo up to 2.25.4/2.26.1. Affected is an unknown function of the file application/src/main/java/run/halo/app/content/comment/ReplyNotificationSubscriptionHelper.java of the SpEL Handler component. Such manipulation leads to improper neutralization.
- CVE-2026-67919Critical
An issue in Halo 2.25.4 allows a remote attacker to execute arbitrary code via the PluginEndpoint.java, installFromUri method, and DefaultPluginApplicationContextFactory components.
- CVE-2026-91772Medium
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.
- CVE-2026-78971Medium
In Halo <= 2.25.4, the plugin management feature allows users to install/update malicious plugins, which could let attackers execute any command with Halo process permissions.
- CVE-2026-67920High
An issue in Halo 2.25.4 allows a remote attacker to execute arbitrary code via the run.halo.app.migration.impl.MigrationServiceImpl.restoreWorkdir(), and org.springframework.util.FileSystemUtils.copyRecursively() components.
- CVE-2026-15326Low
A path traversal vulnerability was found in halo-dev halo up to version 2.24.2 in the ThemeUtils.unzipThemeTo function of ThemeUtils.java during theme installation. Manipulating the metadata.name argument allows remote exploitation, and a public exploit is available.
- CVE-2026-55439Medium
Halo is an open source website building tool. Prior to version 2.24.3, a path traversal vulnerability in the backup download endpoint allows authenticated administrators to read arbitrary files from the server filesystem.
- CVE-2023-27164Medium
An arbitrary file upload vulnerability in Halo up to v1.6.1 allows attackers to execute arbitrary code via a crafted .md file.
Original NVD description (English source)
The reconcile method in the AttachmentReconciler class of the Halo system v.2.20.18LTS and before is vulnerable to XSS attacks.
Vulnerability data from NVD (NIST) · CISA KEV · EPSS