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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.
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4 events from the most recent confirmed update back to the earliest known activity.
CSIRT.SK reported that the CrushFTP authentication bypass was being actively exploited in the wild. The advisory cited Shadowserver observations of dozens of exploitation attempts against internet-exposed CrushFTP servers.
ProjectDiscovery published technical analysis of the CrushFTP authentication bypass, including root-cause details, a proof of concept, and a Nuclei detection template. The post also noted that the issue was initially tracked as CVE-2025-2825 and later re-tracked as CVE-2025-31161 after NIST rejected the original CVE ID.
CrushFTP remediated a critical authentication bypass affecting versions 10.0.0–10.8.3 and 11.0.0–11.3.0. The fix was released in version 10.8.4 for the 10.x branch and 11.3.1 for the 11.x branch, with DMZ mode suggested as a mitigation if patching was not possible.
The vulnerability was published in the NVD as part of the disclosure timeline. ProjectDiscovery notes this publication occurred on March 26, 2025.
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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.
Jul 24, 2026
Attackers have exploited **CrushFTP** authentication-bypass flaw `CVE-2025-31161` by sending a specially crafted `GET` request that impersonates a known username, including the default `crushadmin`, without supplying a password. The forged request yields an authenticated session cookie that can then be reused in a follow-on `POST` request to carry out privileged actions on the server, such as creating a new user, and researchers noted that public proof-of-concept code is available and multiple threat actors have already abused the bug in the wild. Detection guidance shows defenders can identify exploitation by correlating the initial bypass request, the subsequent privileged `POST`, and the server's success response across packets and flows. Netomize published PacketSmith Yara-X logic using `track_state` and `flow_state` to tie those stages together, giving security teams a way to hunt for successful compromise attempts rather than relying on single-request signatures alone.
Jul 7, 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