Arbitrary file write via unsanitized DCC filename
Published Mar 20, 2026 · Updated Mar 20, 2026
Path traversal in Squidowl Halloy 2026.4 and earlier allows remote attackers to write files outside the configured save directory. The DCC receive flow preserves directory separators and parent-directory components from a DCC SEND filename, then PathBuf::join resolves them before File::create writes the payload. File transfer must be enabled with a save directory set; auto-accept makes the write interaction-free, while manual acceptance triggers the same overwrite within Halloy's OS permissions.
Summary
What happened
Path traversal in Squidowl Halloy 2026.4 and earlier allows remote attackers to write files outside the configured save directory. The DCC receive flow preserves directory separators and parent-directory components from a DCC SEND filename, then PathBuf::join resolves them before File::create writes the payload. File transfer must be enabled with a save directory set; auto-accept makes the write interaction-free, while manual acceptance triggers the same overwrite within Halloy's OS permissions.
The record
- CVE
- CVE-2026-32733
- Published
- Mar 20, 2026
- Updated
- Mar 20, 2026
- Vendor
- Squidowl
- Product
- Halloy
- Classifications
- CWE-22, T1105
- Attack vector
- network
- Privileges
- unauthenticated
Timeline
How it unfolded
- Mar 20, 2026CVE publishedPublication date reported by the CVE source.
- Mar 20, 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=<= 2026.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
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
- Single-message DCC SEND path traversal proof of conceptproof of concept · demonstrated
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Technologies
Your stack
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Your stack
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