Cyber Resilience

CVE-2026-32733

HighPublic PoC

Published: 20 March 2026

Published
20 March 2026
Modified
23 March 2026
KEV Added
—
Patch
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CVSS Score v4 8.7 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
EPSS Score 0.0040 31.7th percentile
Risk Priority 55 floored blend · peak EPSS

Summary

CVE-2026-32733 is a high-severity Path Traversal (CWE-22) vulnerability in Halloy Halloy. Its CVSS base score is 8.7 (High).

Operationally, exploitation aligns with the MITRE ATT&CK technique Ingress Tool Transfer (T1105); ranked at the 31.7th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

OWASP Top 10 for Web (2025)

A01:2025 Broken Access Control

EU & UK References

Vulnerability details

Halloy is an IRC application written in Rust. Prior to commit 0f77b2cfc5f822517a256ea5a4b94bad8bfe38b6, the DCC receive flow did not sanitize filenames from incoming `DCC SEND` requests. A remote IRC user could send a filename with path traversal sequences like `../../.ssh/authorized_keys` and…

more

the file would be written outside the user's configured `save_directory`. With auto-accept enabled this required zero interaction from the victim. Starting with commit 0f77b2cfc5f822517a256ea5a4b94bad8bfe38b6, all identified code paths sanitize filenames through a shared `sanitize_filename` function.

CWE(s)
CWE-22

Related Threats

MITRE ATT&CK Enterprise TechniquesAI

T1105 Ingress Tool Transfer Command And Control
Adversaries may transfer tools or other files from an external system into a compromised environment.
attack.mitre.org →
T1098.004 SSH Authorized Keys Persistence
Adversaries may modify the SSH <code>authorized_keys</code> file to maintain persistence on a victim host.
attack.mitre.org →
Why these techniques?

Path traversal in DCC file receive enables arbitrary writes (e.g. SSH keys) with auto-accept, directly facilitating tool ingress and account manipulation.

Confidence: MEDIUM · MITRE ATT&CK Enterprise v19.0

Affected Assets

halloy
halloy
≤ 2026.4

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

SI-10 Information Input Validation
addresses: CWE-22

Validates pathnames and filenames to prevent traversal outside intended directories.

References