CVE-2024-55956
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.
do firstApply mitigations per vendor instructions or discontinue use of the product if mitigations are unavailable.
Can a WAF block it? Partly. Cloudflare publishes WAF a rule written for this CVE. Such rules block the known exploit requests and buy time, but attackers can change the request to get past them, so they do not replace the patch.
Cloudflare · 1 rule (Block) · since 13 Jan 2025
- Cleo Harmony - Auth Bypass - CVE:CVE-2024-55956, CVE:CVE-2024-55953 · Cloudflare Managed Ruleset
Also consider: patch · enable the vendor rule in block mode · input validation · RASP
Based on WAF vendor rules published for this CVE. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Is CVE-2024-55956 being exploited?
Yes. CVE-2024-55956 appears in CISA's Known Exploited Vulnerabilities catalog, which means exploitation in the wild has been confirmed and reported. Treat it as active rather than theoretical, and patch it ahead of higher-scoring vulnerabilities that carry no exploitation evidence.
How severe is CVE-2024-55956?
CVE-2024-55956 is rated Critical with a CVSS score of 9.8. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2024-55956?
Yes. A fix has been recorded for CVE-2024-55956. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2024-55956 affect?
CVE-2024-55956 affects cleo:harmony, cleo:lexicom, cleo:vltrader. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
public exploits
Public exploit code: 1 Metasploit module · 1 Nuclei template
- exploit/multi/http/cleo_rce_cve_2024_55956 · exploit · excellent
- Cleo Harmony < 5.8.0.24 - File Upload Vulnerability · detection template · critical
Listed so you can judge urgency, not as a recommendation to run anything. GitHub “proofs of concept” are unvetted: some are fake or carry malware. Exploit-DB marks the entries its staff verified.
cisa ssvc
- exploitation
- active
- automatable
- no
- technical impact
- total
Assessed by CISA 16 Dec 2024 (SSVC 2.0.3).
timeline
- 13 Dec 2024Published
- 16 Dec 2024CISA SSVC assessment: exploitation active · 2 days later
- 17 Dec 2024Added to CISA KEV (exploited in the wild) · 1 day later
- 7 Jan 2025CISA remediation due date (US federal agencies) · 21 days later
- 5 Aug 2026CVE record last updated · 575 days (about 2 years) later
- 2 Nov 2026Analysed by vulneraibility.com · 90 days (about 3 months) later
- Linksupport.cleo.com /hc/en-us/articles/28408134019735-Cleo-Product-Security-Advisory-CVE-Pending
- Linksupport.cleo.com /hc/en-us/articles/28408134019735-Cleo-Product-Security-Update
- Linkhuntress.com /blog/threat-advisory-oh-no-cleo-cleo-software-actively-being-exploited-in-the-w
- Linkcisa.gov /known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-55956
sources
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA KEV catalog: exploitation, date added, due date
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
- Metasploit Framework: exploit and scanner modules
- Nuclei templates: detection templates
- Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.