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Linkr CVE-2025-59334

CRITICAL
Improper Verification of Cryptographic Signature (CWE-347)
2025-09-16 security-advisories@github.com
9.6
CVSS 3.1 · GitHub Advisory
View

Vulnerability Assessment

Weakness
CWE
OWASP Top 10:2025
A04:2025 - Cryptographic Failures
ASVS 5.0
V11 - Cryptography Signature verification
Impact

CVSS score of 9.6 (CRITICAL). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required. Public proof-of-concept exploit code is available. EPSS exploitation probability: 0.11%.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the critical-severity affected system.

Act Now Prioritize within 24-48h. Why: CRITICAL severity + public POC available.
Patch available 0.1% exploitation probability (EPSS)

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AnalysisAIv1 – Mar 28, 2026

Linkr is a lightweight file delivery system that downloads files from a webserver. Rated critical severity (CVSS 9.6), this vulnerability is remotely exploitable, no authentication required, low attack complexity. Public exploit code available.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-347. Linkr is a lightweight file delivery system that downloads files from a webserver. Linkr versions through 2.0.0 do not verify the integrity or authenticity of .linkr manifest files before using their contents, allowing a tampered manifest to inject arbitrary file entries into a package distribution. An attacker can modify a generated .linkr manifest (for example by adding a new entry with a malicious URL) and when a user runs the extract command the client downloads the attacker-supplied file without verification. This enables arbitrary file injection and creates a potential path to remote code execution if a downloaded malicious binary or script is later executed. Version 2.0.1 adds a manifest integrity check that compares the checksum of the original author-created manifest to the one being extracted and aborts on mismatch, warning if no original manifest is hosted. Users should update to 2.0.1 or later. As a workaround prior to updating, use only trusted .linkr manifests, manually verify manifest integrity, and host manifests on trusted servers. Affected products include: Mohammadzain2008 Linkr. Version information: through 2.0.0.

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Severity by source

GitHub Advisory PRIMARY 9.6 CRITICAL
AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Primary rating from GitHub Advisory · only source for this CVE.

CVSS VectorGitHub Advisory

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Changed
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

3
Patch released
Mar 28, 2026 - 19:12 nvd
Patch available
PoC Detected
Oct 08, 2025 - 19:16 vuln.today
Public exploit code
CVE Published
Sep 16, 2025 - 17:15 nvd
CRITICAL 9.6

DescriptionGitHub Advisory

Linkr is a lightweight file delivery system that downloads files from a webserver. Linkr versions through 2.0.0 do not verify the integrity or authenticity of .linkr manifest files before using their contents, allowing a tampered manifest to inject arbitrary file entries into a package distribution. An attacker can modify a generated .linkr manifest (for example by adding a new entry with a malicious URL) and when a user runs the extract command the client downloads the attacker-supplied file without verification. This enables arbitrary file injection and creates a potential path to remote code execution if a downloaded malicious binary or script is later executed. Version 2.0.1 adds a manifest integrity check that compares the checksum of the original author-created manifest to the one being extracted and aborts on mismatch, warning if no original manifest is hosted. Users should update to 2.0.1 or later. As a workaround prior to updating, use only trusted .linkr manifests, manually verify manifest integrity, and host manifests on trusted servers.

Executive ViewAI

Why It Matters

Organizations using Linkr face critical risk from CVE-2025-59334, a signature bypass vulnerability rated CVSS 9.6. Successful exploitation could critically impact the confidentiality, integrity, and availability of affected systems. Proof-of-concept code is publicly available, increasing the risk of exploitation. A patch is available and should be applied immediately given the critical severity.

Business Impact: Severe
Compensating Controls

Apply vendor patch. If immediate patching is not feasible: (1) Implement network-level access controls to limit exposure; (2) Enable enhanced monitoring and alerting; (3) Apply principle of least privilege.

Threat Intelligence Overview

EPSS Score
0.1%
Top 71% exploitable
Exploit
POC
Public exploit code exists

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity CRITICAL
CISA KEV No
Public POC Yes
EPSS 0.1%
Patch available Yes
Active threat No
Deciding rule
CRITICAL severity + public POC available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Out-of-Cycle
Exploitation· derived
Poc
System Exposure· derived
Open
Automatable· derived
No
Human Impact
Very High

Priority Score

68
Low Medium High Critical
KEV: 0
EPSS: 0
CVSS: +48
PoC: +20
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.

Affected Products (CPE)GitHub Advisory

cpe:2.3:a:mohammadzain2008:linkr:*:*:*:*:*:*:*:*

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