Exploited vulnerability · CISA KEV

Is CVE-2023-49105 exploited? Yes: in CISA KEV since 27 Aug 2026

Gociux · ownCloud · data: CISA KEV, CVE record, FIRST EPSS

Yes. CVE-2023-49105, ownCloud Improper Authentication Vulnerability, is being exploited in the wild. CISA added it to its Known Exploited Vulnerabilities catalog on 27 Aug 2026, 1010 days after it was published. It affects ownCloud. If you run it, CISA's required action is: 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.

What it is

ownCloud contains an improper authentication vulnerability that allows an attacker to access, modify, or delete any file without authentication if the username of a victim is known, and the victim has no signing-key configured.

What to do

1. Check whether you run it. Look for ownCloud in your asset inventory, including appliances and cloud images. Stack check lists every exploited ownCloud CVE at once.
2. Apply the fix. 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.
3. If you can't patch today, take the affected service off the internet or restrict who can reach it, and check its logs for signs of compromise since 21 Nov 2023.
4. Get told next time. Email alerts when CISA adds a CVE for ownCloud.

References

• owncloud.org/security
• owncloud.com/security-advisories/webdav-api-authentication-bypass-using-
• nvd.nist.gov/vuln/detail/CVE-2023-49105

Sources: CISA KEV (exploitation, ransomware use, required action, due date), the CVE record (publication date, CVSS, CNA), NVD and FIRST EPSS (live score). More: all KEV additions in August 2026 · ownCloud scorecard · act-now radar.