CyberSecBulletin
CVE-2025-59334NVD status: Analyzed

Linkr: Improper Verification of Cryptographic Signature

Published Updated By the CyberSecBulletin desk

CVE-2025-59334 is a high-severity improper verification of cryptographic signature vulnerability in Linkr from Mohammadzain2008, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, but only if a user takes part, for example by opening a link or file. Affected Linkr versions: < 2.0.1. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.43% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Check which version of Linkr you run against the affected versions below, and install the vendor's latest release.
  2. Read the advisory on github.com for workarounds and exact fixed builds.
  3. Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
  4. Because the attack needs a user to take part, warn users about unexpected links and files related to this product until it is patched.

Affected products and versions

VendorProductAffected versionsFixed in
Mohammadzain2008Linkr< 2.0.1Not stated

Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.

How the severity score breaks down

Attack vector
NetworkCan be exploited remotely over a network, including the internet.
Attack complexity
LowNo special conditions are needed; the attack works reliably.
Privileges required
NoneNo account or login is needed.
User interaction
RequiredA user must take an action such as opening a file or link.
Scope
UnchangedImpact stays within the vulnerable component.
Confidentiality
HighAll data handled by the component can be read.
Integrity
HighData or code can be modified at will.
Availability
HighThe component can be taken down completely.

Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.19.6CriticalCNA (github.com)
CVSS 3.18.8HighNVD

Official description

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.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Improper Verification of Cryptographic Signature

The product does not verify, or incorrectly verifies, the cryptographic signature for data.

More Improper Verification of Cryptographic Signature vulnerabilities (CWE-347)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: poc, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Recent Improper Verification of Cryptographic Signature vulnerabilities

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