What is CVE-2025-31161?

CVE-2025-31161 is CrushFTP Authentication Bypass Vulnerability. The supplied enrichment data classifies it as Auth Bypass mapped to CWE-305 CWE-305.

Which versions are affected?

Affected product and version evidence is listed in the product table above. Current public advisories should be checked for exact version scope before patch targeting is finalized.

Is there active exploitation?

Yes: CISA KEV signal present. If exploitation is not confirmed from current sources, teams should document that status and continue monitoring KEV, vendor, and telemetry updates.

Is there a public exploit?

64 public PoC repositories reported; 1 marked weaponized in current dataset. Public exploit or PoC availability should raise triage priority, especially for exposed or business-critical systems.

How can defenders detect it?

Start with web/proxy/WAF logs, application logs, network IDS/IPS, identity provider logs, authentication audit logs where available. Look for vulnerability-class behavior, product errors, suspicious authentication events, exploit probes, and abnormal process activity based only on evidence that applies to the affected product.

How should teams prioritize it?

Prioritize CVE-2025-31161 using CVSS 9.8, EPSS 100%, KEV status, public PoC status, and asset exposure. Internet-facing, privileged, or business-critical deployments should be handled first.

Are workarounds available?

The supplied mitigation guidance says to apply vendor patches and restrict external exposure until fixed. Fixed-version evidence is listed in the mitigation section above.

Which threat actors are linked publicly?

Publicly linked actor or ransomware signals in the supplied enrichment data: Mana Team (), RomCom (), Pat Bear (), SCATTERED SPIDER (), Shadow Network (), Ransomware use: Known. Do not attribute exploitation to a threat actor unless the source evidence explicitly supports that linkage.

What should be done in the next 24 hours?

Identify exposed assets running affected vendor/product/version combinations. Treat as emergency remediation because CISA KEV status is present. Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class. Open remediation tickets with affected assets, owners, evidence status, and detection coverage so decisions are traceable.

CISA KEVRansomwarecriticalAuth Bypasspublic exploit

CVE-2025-31161

CVE-2025-31161 — CrushFTP Authentication Bypass Vulnerability

Q: Is it in CISA KEV?

Yes. The supplied enrichment data lists CVE-2025-31161 in CISA KEV with required action: Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.. KEV status should be monitored because it can change after initial disclosure or after exploitation becomes publicly confirmed.

CrushFTP 10 before 10.8.4 and 11 before 11.3.1 allows authentication bypass and takeover of the crushadmin account (unless a DMZ proxy instance is used), as exploited in the wild in March and April 2025, aka "Unauthenticated HTTP(S) port access." A race condition exists in the AWS4-HMAC (compatible with S3) authorization method of the HTTP component of the FTP server. The server first verifies the existence of the user by performing a call to login_user_pass() with no password requirement. This will authenticate the session through the HMAC verification process and up until the server checks for user verification once more. The vulnerability can be further stabilized, eliminating the need for successfully triggering a race condition, by sending a mangled AWS4-HMAC header. By providing only the username and a following slash (/), the server will successfully find a username, which triggers the successful anypass authentication process, but the server will fail to find the expected SignedHeaders entry, resulting in an index-out-of-bounds error that stops the code from reaching the session cleanup. Together, these issues make it trivial to authenticate as any known or guessable user (e.g., crushadmin), and can lead to a full compromise of the system by obtaining an administrative account.

Published Apr 3, 2025Updated Jun 17, 2026Sources: NVD, CrushFTP (CNA), CISA, FIRST EPSS, GitHub, Exploit-DB, SOCRadar CTI

Triage

Is it exploited, how likely is exploitation, what does it touch, and how severe do the scoring sources call it.

Exploitation

Confirmed

CISA KEV, listed Apr 7, 2025

EPSS

100%

top of FIRST's scoreset

Affects

CrushFTP

2 products listed

CVSS base

9.8

critical

CISA SSVC assessment

Three decision points CISA publishes for the CVEs it assesses · SSVC 2.0.3. A stakeholder decision, not a severity score.

CISA

Exploitation

Active

none · proof-of-concept · active

Automatable

Yes

can an attacker script all four kill-chain steps

Technical impact

Total

partial · total control of the vulnerable component

Remediation

The vendor's own words where we have them.

Upgrade CrushFTP to a fixed release. Apply vendor patches per advisory and restrict external exposure of the affected component until patched.

CISA required action

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Federal deadline Apr 28, 2025 — passed 508 days ago

First 24 hours

Ordered from the record's own fields — exposure first, because you cannot patch what you have not found.

Identify exposed assets running affected vendor/product/version combinations.
Treat as emergency remediation because CISA KEV status is present.
Search available logs for exploit probes, errors, authentication anomalies, or suspicious child processes matching the vulnerability class.

Affected scope

Vendor, product and version as the advisories word them.

Vendor	Product	Versions	Status
CrushFTP	CrushFTP	10 to < 10.8.4	Vulnerable
CrushFTP	CrushFTP	11 to < 11.3.1	Vulnerable

Attack characteristics

The CVSS vector, decoded. It describes the attack, not your exposure to it.

Availability

High

Confidentiality

High

Integrity

High

Scope

Unchanged

Attack Complexity

Low

Attack Vector

Network

Privileges Req

None

User Interaction

None

Every base score collected

Sources score independently and disagree; each row says who scored it and under which version.

Score	Version	Severity	Expl.	Impact	Source
9.8	CVSS 3.1	critical	3.9	5.9	MITRE (CNA), NVD, CrushFTP (CNA)

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

What this weakness leads to

MITRE's own consequences and mitigations for the weakness class — the authority's wording, not guidance derived from the CVSS vector.

MITRE

CWE-305 · Authentication Bypass by Primary Weakness

Bypass Protection Mechanism::

Weakness & attack patterns

CWE-305

Inferred from the weakness class — not observed against this CVE.

CAPEC-115 · Authentication BypassCAPEC-94 · Adversary in the Middle

CISA KEV details

CISA lists a CVE here once it has evidence of exploitation against real targets.

CISAThat month →

Listed

Apr 7, 2025

Federal deadline

Apr 28, 2025

passed 508 days ago

Ransomware use

Known

CISA records ransomware use only for campaigns it has confirmed, so “Unknown” means unrecorded, not ruled out. The deadline binds US federal agencies; for everyone else it is a date to argue against.

Public exploit

Capability, not use: code existing is a different claim from anyone running it.

Repositories

1 of the 5 sampled are weaponized

Exploit entries

Exploit-DB and CTI exploit indexes

Social mentions

Posts naming this CVE. Attention, not evidence of exploitation — it spikes on disclosure and decays whether or not anything is exploited.

Detection

Read off the CVSS vector and the weakness class. Starting points, not rules we have tested.

Search application, proxy, and WAF logs for requests touching /).
Prioritize edge telemetry for network-reachable CrushFTP.
Monitor for scanner or exploit-pattern traffic after 64 public PoC repositories were reported.

web/proxy/WAF logsapplication logsnetwork IDS/IPSidentity provider logsauthentication audit logs

Groups associated with this CVE

Groups reported in connection with this vulnerability. A reported association, not a confirmed observation of that group using it — and not scoped to any sector or campaign.

Mana TeamRomComPat BearSCATTERED SPIDERShadow Network

5 more threat groups on this CVEShowing 5 of 10 · Attribution, campaigns and the malware each one runsUnlock free

Timeline

What happened to this CVE, newest first — with the readings a source repeats on a schedule counted underneath rather than listed.

2026
Added · CVSS 3.1 9.8 (AV:N)
Jun 17, 2026 · NVD
Cve is exploited eserror/CVE-2025-31161
Feb 23, 2026 · SOCRadar CTI
Cve is exploited Shisones/CVE-2025-31161
Feb 23, 2026 · SOCRadar CTI
Cve is exploited Dairrow/CVE-2025-31161
Jan 22, 2026 · SOCRadar CTI
2025
Added · remote entry: CrushFTP 11.3.1 - Authentication Bypass
May 18, 2025 · Exploit-DB
Added to CISA KEV catalog
Apr 7, 2025 · CISA
Initial · CVE published
Apr 3, 2025 · NVD

Source activity

Readings a source repeats on a schedule, counted rather than listed.

10×SVRS was changedOct 25, 2025 – May 15, 2026 · SOCRadar CTI
6×Tweets · 1 time tweeted.Dec 6, 2025 – May 15, 2026 · SOCRadar CTI
6×Github ReposDec 7, 2025 – Apr 20, 2026 · SOCRadar CTI
3×CVE modified by MITRE: CVSS metrics updated.Oct 21, 2025 – Oct 31, 2025 · SOCRadar CTI
1×2 times mentioned on 2 Telegram channelsJan 26, 2026 · SOCRadar CTI

References

13 on the record

crushftp.com/crush11wiki/Wiki.jsp?page=Update#section-Update-VulnerabilityInfo
Vendor Advisory, NIST
outpost24.com/blog/crushftp-auth-bypass-vulnerability/
Third Party Advisory, GITHUB, NIST
attackerkb.com/topics/k0EgiL9Psz/cve-2025-2825/rapid7-analysis
Exploit, Third Party Advisory, NIST, GITHUB
projectdiscovery.io/blog/crushftp-authentication-bypass
Exploit, Third Party Advisory, GITHUB, NIST
www.darkreading.com/vulnerabilities-threats/disclosure-drama-clouds-crushftp-vulnerability-exploitation
Press/Media Coverage, NIST
www.huntress.com/blog/crushftp-cve-2025-31161-auth-bypass-and-post-exploitation
Exploit, Third Party Advisory, GITHUB, NIST
www.infosecurity-magazine.com/news/crushftp-flaw-exploited-disclosure/
Press/Media Coverage, GITHUB, NIST
www.vicarius.io/vsociety/posts/cve-2025-31161-detect-crushftp-vulnerability
Exploit, Third Party Advisory, GITHUB, NIST

Coverage

12 stories from the feeds we poll

7 more reports on this CVEShowing 5 of 12 · Vendor research and security press coverageUnlock free

Elsewhere on this site

CrushFTPevery CVE for this vendor
April 2025what else CISA listed
Auth Bypasssame class
CWE-305other pages naming this weakness

Not in any source we poll

Listed rather than left blank: an empty field and an unmeasured one look identical on screen, and only one is a reason to look elsewhere.

No confirmed IOCs, IP addresses, domains, file hashes, or malware artifacts supplied.
No organization-specific asset inventory, compensating-control status, or patch deployment evidence supplied.
No exploit packet captures, log samples, or incident case IDs supplied.

Answered from this record1

What should defenders know first?

CVE-2025-31161 is CrushFTP Authentication Bypass Vulnerability, a critical vulnerability affecting CrushFTP from CrushFTP. The current evidence lists it in CISA KEV, and the exploit status is: Yes: CISA KEV signal present. Public exploit evidence is: 64 public PoC repositories reported; 1 marked weaponized in current dataset. The affected-version evidence is listed in the key facts and affected products tables. Defenders should first verify whether exposed or business-critical assets run those versions, then apply vendor patches or mitigations, restrict reachable attack surface, and preserve logs for detection review. CVSS 9.8 describes technical severity, while EPSS 100% helps estimate near-term exploit likelihood; neither replaces asset context. Unknown fields should remain explicit in tickets, and threat actor, IOC, victimology, or payload claims should not be added unless a cited source supports them. Monitor CISA KEV, vendor advisories, NVD changes, public PoC repositories, and internal telemetry for update triggers.