FalehSec Exploited-vulnerability triage · joined from CISA KEV, NVD CVSS and EPSS

CVE-2024-55956

Cleo · Multiple Products · Cleo Multiple Products Unauthenticated File Upload Vulnerability

Verdict
Patch first · actively exploited, reachable from the internet without credentials, and in the top 1% of CVEs by near-term exploitation probability

Added to CISA KEV 2024-12-17 · exploited in the wild for 649 days · used in ransomware campaigns

What an attacker can reach How likely Time What CISA says to do Sources All 545

What an attacker can reach

CVSS 9.8 CRITICAL. The score is a summary; these three components are the part that decides whether something scanning the internet can use it.

Attack vectornetworkreachable over the network, with no local access needed
Privileges requirednoneneeds no credentials at all
User interactionnonecan be triggered with nobody interacting with the page or request
Base vectorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
WeaknessCWE-77

This describes the vulnerability. It says nothing about whether your systems run it.

How likely

EPSS puts the probability of exploitation in the next 30 days at 0.9397, which places it in the top 1% of all tracked CVEs. The percentile is the more useful half: 0.18 in absolute terms sounds low until you know most of the internet-facing software in the world scores under that.

EPSS probability0.9397
Percentile0.998 — top 1%

Time

Added to KEV2024-12-17
Days exploited649
Federal remediation duenot set
Ransomware useknown to be used in ransomware campaigns

What CISA says to do

Apply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.

In Cleo Harmony before 5.8.0.24, VLTrader before 5.8.0.24, and LexiCom before 5.8.0.24, an unauthenticated user can import and execute arbitrary Bash or PowerShell commands on the host system by leveraging the default settings of the Autorun directory.

Sources