Host file overwrite via A2A inbox symlink
Published Sep 14, 2026 · Updated Sep 14, 2026
Link following in NanoCo NanoClaw 2.1.0 through 2.1.17 allows attackers to write host files via forwarded A2A attachments. The forwardAttachedFiles function creates and copies into the target inbox without lstat or realpath containment checks, so a preplaced inbox symlink redirects the host-side destination. A compromised or prompt-injected target agent must control its session directory and receive or cause a transfer; resulting writes can corrupt any host-process-writable file.
Summary
What happened
Link following in NanoCo NanoClaw 2.1.0 through 2.1.17 allows attackers to write host files via forwarded A2A attachments. The forwardAttachedFiles function creates and copies into the target inbox without lstat or realpath containment checks, so a preplaced inbox symlink redirects the host-side destination. A compromised or prompt-injected target agent must control its session directory and receive or cause a transfer; resulting writes can corrupt any host-process-writable file.
The record
- CVE
- CVE-2026-90807
- Published
- Sep 14, 2026
- Updated
- Sep 14, 2026
- Vendor
- NanoCo
- Product
- NanoClaw
- Classifications
- CWE-59, T1565.001
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Sep 14, 2026CVE publishedPublication date reported by the CVE source.
- Sep 14, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
Compare your product and version with the public record. A matching version still requires validation against your environment.
Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.1.0
- Affected versionversion=2.1.1
- Affected versionversion=2.1.10
- Affected versionversion=2.1.11
- Affected versionversion=2.1.12
- Affected versionversion=2.1.13
- Affected versionversion=2.1.14
- Affected versionversion=2.1.15
- Affected versionversion=2.1.16
- Affected versionversion=2.1.17
- Affected versionversion=2.1.2
- Affected versionversion=2.1.3
- Affected versionversion=2.1.4
- Affected versionversion=2.1.5
- Affected versionversion=2.1.6
- Affected versionversion=2.1.7
- Affected versionversion=2.1.8
- Affected versionversion=2.1.9
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
- NanoClaw issue 2828 verification harnessproof of concept · 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
Check the software in your environment
Book a demo to see how Hinoki identifies affected software and validates exploitability in your environment.
Book a demo