Actively exploited vulnerability

JFrog Artifactory: authentication bypass flaw under attack

CVE-2026-42018 · JFrog Artifactory Improper Authentication Vulnerability

Business software7.5 high

What is affected

JFrog Artifactory is mostly run by companies, schools and public bodies, not on home computers. You are unlikely to have it yourself, but organisations that hold your data may. Breaches that start with flaws like this one are how personal data ends up leaked.

JFrog Artifactory contains an improper authentication vulnerability that could return an internal anonymous-user token to an unauthenticated caller when anonymous access is disabled, potentially exposing sensitive resources.

CISA's description

What an attacker can do

This is a authentication bypass flaw. It lets an attacker get in without a valid username and password and act as a legitimate user, often as an administrator.

How it is reached
Over the internet or network
Access the attacker needs
No account needed
Does the victim have to do something?
No, works without the victim doing anything

What to do

  1. At home: nothing to install. Keep your own devices updated and use a different password for every service, so that a breach at one organisation does not open your other accounts.
  2. If you administer JFrog Artifactory at work: apply the vendor's fix or mitigation now and review logs for signs of compromise, because the flaw was being exploited before it was listed.
  3. If the product is past its support date and no fix exists, take it off the internet or retire it.

Apply mitigations in accordance with vendor instructions, ensuring compliance with CISA’s BOD 26-04 Prioritizing Security Updates Based on Risk (see URL in Notes) guidance and CISA’s “Forensics Triage Requirements” (see URL in Notes). Follow applicable BOD 26-04 guidance for cloud services or discontinue use of the product if mitigations are unavailable. Stakeholders are responsible for evaluating each asset's internet exposure and ensuring adherence to BOD 26-04 patching guidelines.

Action required by CISA for US federal agencies

Vendor advisories and fixes

How urgent is it

CISA added this vulnerability to its Known Exploited Vulnerabilities catalogue on September 11, 2026, which means there is reliable evidence of attacks in the wild. US federal agencies must fix it by September 25, 2026, a deadline that has already passed. That deadline does not bind anyone else, but it shows how seriously the agency rates it.

The EPSS model estimates a 9.8% probability that this flaw will be exploited somewhere in the next 30 days. That is higher than 95% of all scored vulnerabilities.

Its CVSS severity score is 7.5 out of 10 (high), as recorded in the US National Vulnerability Database.

Technical description

JFrog Artifactory could return an internal anonymous-user token to an unauthenticated caller when anonymous access is disabled, potentially exposing sensitive resources.

NIST National Vulnerability Database
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