Host file read and overwrite via hardlinks
Published Jul 18, 2026 · Updated Jul 18, 2026
Improper link resolution in AstrBot 4.25.0 through 4.25.5 allows local users to read or overwrite host files through hardlinks. The _is_path_within_allowed_roots check validates only pathname containment, so _normalize_rw_path forwards an in-workspace hardlink to filesystem read and write sinks without checking the final inode. Exploitation requires local runtime mode, a non-admin member session, and an attacker-created hardlink on the same filesystem; access remains limited by the AstrBot process permissions.
Summary
What happened
Improper link resolution in AstrBot 4.25.0 through 4.25.5 allows local users to read or overwrite host files through hardlinks. The _is_path_within_allowed_roots check validates only pathname containment, so _normalize_rw_path forwards an in-workspace hardlink to filesystem read and write sinks without checking the final inode. Exploitation requires local runtime mode, a non-admin member session, and an attacker-created hardlink on the same filesystem; access remains limited by the AstrBot process permissions.
The record
- CVE
- CVE-2026-16077
- Published
- Jul 18, 2026
- Updated
- Jul 18, 2026
- Vendor
- AstrBotDevs
- Product
- AstrBot
- Classifications
- CWE-59, T1565.001, T1005
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Jul 18, 2026CVE publishedPublication date reported by the CVE source.
- Jul 18, 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=4.25.0
- Affected versionversion=4.25.1
- Affected versionversion=4.25.2
- Affected versionversion=4.25.3
- Affected versionversion=4.25.4
- Affected versionversion=4.25.5
What conditions does exploitation require?
What is affected?
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
- AstrBot local-runtime hardlink boundary-bypass reproductionfunctional · demonstrated
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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