CVE-2026-85396

rubyzip before 3.4.0 Path Traversal in Zip::Entry#extract via Sibling-Directory Prefix

HIGH
7.5
CVSS Score
Published: September 3, 2026 at 06:54 PM UTC
Updated: September 24, 2026 at 08:47 PM UTC
2 products affected across 2 vendorsRubyzipRubyzip

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Severity
HIGH7.5
Exploit prediction
EPSS 0.6%
SSVC
No known exploit

Description

rubyzip versions before 3.4.0 contain a path traversal vulnerability in Zip::Entry#extract that fails to properly validate extraction paths using prefix comparison without trailing separators. Attackers can craft archive entries with names like ../upload_backup/owned.sh to write files outside the intended extraction directory into sibling paths sharing the destination prefix.

Affected

Our own answer: ranges merged, affected separated from platform-only, with confidence and review flags.

v < 3.4.0
Affected range stops below 3.4.0, so it looks safe — our inference, not a vendor statement
v < 3.4.0
Vendor states this is fixed in 3.4.0 (unaffected)

Remediation

No guide yet

No remediation guidance has been written for this CVE yet. What the record does show:

SSVC — Action Prioritization

SSVCNo known exploitAutomatablePartial impact

SSVC signals action urgency (what to patch first), separate from CVSS which measures severity.

CVSS

7.5HIGHVulnCheck
Attack Vector
NETWORK
Complexity
LOW
Privileges
NONE
User Interaction
NONE
Scope
UNCHANGED
Confidentiality
NONE
Integrity
HIGH
Availability
NONE
Vector?

Quick Info

StatusAWAITING ANALYSIS
CWE
CWE-22

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