Arc Enterprise cluster FSM applyRegisterFile accepts arbitrary file paths without validation, enabling cluster-wide path-traversal worm primitive

published 2026-08-21 2 mo ago modified 2026-10-12 28 d ago also EUVD-2026-64192

cvss: 8.3; version 4.0, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 13%
public exploits: 0; none known

Arc is an open, SQL-native time-series database for telemetry. Prior to version 26.06.1, Arc Enterprise's Raft FSM (`internal/cluster/raft/fsm.go:applyRegisterFile`) accepts attacker-chosen file paths in manifest-registration proposals without validating them against the configured storage backend. The only check is that the path is non-empty. There is no parent-traversal (`..`) rejection, no allowlist of legitimate prefixes, no scheme restriction (`s3://` vs local), and no length bound. This is fixed in 2026.06.1. Some workarounds are available. Restrict cluster network access to known-trusted peers via strict firewall rules, audit the cluster manifest for unexpected paths (any path not matching the configured storage backend root is suspect), and/or disable cluster mode until the fix is available.

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 2 mo ago (2026-08-24)

Exploit prediction

0.22% chance of exploitation in the next 30 days, higher than 13% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	4.0	8.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/SA:N
CNA	4.0	8.3	CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:H/VA:N/SC:N/SI:H/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

Affected products

Basekick-Labs arc

Classification

Weakness

CWE-22 Improper Limitation of a Pathname to a Restricted Directory
CWE-345 Insufficient Verification of Data Authenticity
CWE-913 Improper Control of Dynamically-Managed Code Resources

References

github.com /Basekick-Labs/arc/security/advisories/GHSA-f85q-mvg8-qf37

Sources

CVE List CVE-2026-48105
NVD CVE-2026-48105

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

Summary