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A critical CrushFTP zero-day, tracked as CVE-2025-54309, has been reported as actively exploited in the wild, prompting urgent warnings from security researchers and national incident responders. The flaw affects CrushFTP 11.x and 10.x builds including 11.3.4_23 and later and 10.8.5 and later, and can allow attackers to bypass authentication and obtain administrator access over HTTPS when the DMZ proxy service is disabled. The issue has been assigned a CVSS 3.1 score of 9.0 and has been linked to improper AS2 validation in vulnerable versions.
CrushFTP released fixes in 11.3.4_26 and 10.8.5_12, and defenders were urged to patch immediately or restore the application’s original configuration from clean backups created on or before July 16 if patching is not yet possible. Reported indicators of compromise include changes to MainUsers/default/user.xml containing the string last_logins, creation of unknown administrator accounts with long identifiers, unusual UI behavior, administrator logins from unfamiliar IP addresses, and altered permissions on sensitive directories.
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3 events from the most recent confirmed update back to the earliest known activity.
CrushFTP developers released updates to fix CVE-2025-54309, an authentication bypass vulnerability affecting certain 10.x and 11.x versions. The recommended fixed versions are 11.3.4_26 and 10.8.5_12.
Rapid7 and CSIRT.SK reported that CVE-2025-54309 was being actively exploited as a zero-day. The flaw can allow attackers to bypass authentication and gain administrator access over HTTPS when the DMZ proxy service is disabled.
CSIRT.SK advised administrators who could not patch immediately to restore CrushFTP's original configuration from clean backups created on or before July 16. The same guidance highlighted indicators of compromise such as altered user.xml entries, unknown administrator accounts, and suspicious admin logins.
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A critical **CrushFTP** zero-day was reported as actively exploited, allowing an unauthenticated attacker to escape the product’s virtual file system and download files from the underlying system. The flaw was discovered by Simon Garrelou of **Airbus CERT**, and public reporting said observed attacks primarily targeted organizations in the **United States**, with some suspicion that the activity was politically motivated. Defenders were urged to patch immediately because affected deployments could suffer sensitive information disclosure without valid credentials. Guidance pointed users running versions older than **11.1**—particularly **version 9**—to upgrade to fixed releases **10.7.1** or **11.1.0**, while CrushFTP’s update documentation provided the vendor’s release path for remediation.
Jul 24, 2026
CrushFTP warned customers to patch an actively exploited zero-day, now tracked as **CVE-2024-4040**, that lets unauthenticated attackers escape the product’s virtual file system sandbox and download system files. The company said the flaw was reported and patched immediately, with fixes released in **CrushFTP v10.7.1** and **v11.1.0**; organizations still running **v9** were urged to upgrade to v11 or apply updates through the product dashboard. Airbus CERT also published a public scanner for the vulnerability on GitHub, underscoring rapid defender and researcher interest in identifying exposed systems. CrowdStrike said the bug was exploited in the wild in targeted attacks against multiple U.S. organizations and assessed the activity as an intelligence-gathering campaign that was likely politically motivated. CrushFTP added that deployments using a **DMZ** in front of the main instance were protected from the observed attacks, while internet exposure remained a major concern: Shodan data cited in reporting showed roughly **2,700** CrushFTP instances with their web interface accessible online, expanding the pool of potentially vulnerable targets.
Jun 29, 2026
A critical CrushFTP authentication bypass flaw, initially tracked as `CVE-2025-2825` and later re-tracked as `CVE-2025-31161`, allows unauthenticated remote attackers to log in as valid users by sending a crafted S3-compatible `Authorization` header. The bug affects versions `10.0.0–10.8.3` and `11.0.0–11.3.0`, and stems from flawed authentication logic in `loginCheckHeaderAuth()` that can skip password verification when processing AWS4-HMAC-style credentials. Researchers reported that an attacker may need only a username in the `Credential` field and a syntactically valid `CrushAuth` cookie format, without successful signature validation, to gain unauthorized access. Security teams reported active exploitation against internet-exposed CrushFTP servers, with Shadowserver observing dozens of attack attempts in the wild. CrushFTP addressed the issue in `10.8.4` and `11.3.1`, including changes to properly validate passwords and a default-disabled setting to block the vulnerable path; defenders were urged to upgrade immediately, restrict external access, or enable DMZ mode where patching is not yet possible. ProjectDiscovery also released a Nuclei detection template that checks for successful user-list retrieval via the bypass, underscoring the need to identify exposed and vulnerable instances quickly.
Jul 24, 2026