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CVE-2025-54309

From Exploited flaws, HARD’s guide to the flaws being used in attacks · Checked
This article is about a flaw in CrushFTP. For every flaw being used in attacks, see Exploited flaws; for CrushFTP’s, see CrushFTP flaws being used in attacks.

CVE-2025-54309 is a security flaw in CrushFTP, software companies use to send and receive files. Attackers are using a flaw in CrushFTP. The US Cybersecurity and Infrastructure Security Agency (CISA) added it to its catalog of flaws known to be used in attacks on 22 Jul 2025.[1]

CrushFTP is business software or equipment. Most families won’t have it, but attackers break into it to get inside companies, and from there to what those companies hold about their customers, patients and staff. Fixed in version 10.8.5 and 11.3.4_23 of CrushFTP.

Description

CISA calls it an unprotected alternate channel in CrushFTP CrushFTP. In its words: “CrushFTP contains an unprotected alternate channel vulnerability. When the DMZ proxy feature is not used, mishandles AS2 validation and consequently allows remote attackers to obtain admin access via HTTPS.”[1]

The underlying weakness is CWE-420, in MITRE’s list of common software weaknesses.[2]

It scores 9.8 out of 10 on the Common Vulnerability Scoring System, which rates it critical, scored by NVD using CVSS 3.1.[2]

Affected versions

NVD’s record lists these fixed versions: in each line, everything before the version shown is affected.[2]

ProductFixed in
CrushFTP10.8.5
CrushFTP11.3.4_23

Most families won’t have CrushFTP; it’s for whoever looks after IT at work.

Exploitation

CISA added it to its catalog of known exploited vulnerabilities on 22 Jul 2025, 4 days after it was made public. CISA lists a flaw only when it has reliable evidence of it being exploited, and gave US federal agencies until 12 Aug 2025 to fix it.[1]

FIRST’s Exploit Prediction Scoring System, which estimates how likely a flaw is to be used in attacks in the next 30 days from what it sees across the internet, puts it at 93%. That’s in the top 1% of the flaws it scores.[4]

CISA assesses it as not automatable: each attack takes some work.

CISA doesn’t say who was attacked, or how.

Fix

CrushFTP has published a fix or advice.[3] CISA’s 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.”[1]

  1. Check whether you use it.CrushFTP is business software or equipment, so most families won’t have it. If you run a business, or work from home on company equipment, ask whoever looks after your IT.
  2. Send this page to your IT person.Ask them to confirm it’s fixed (fixed in version 10.8.5 and 11.3.4_23 of CrushFTP), or not in use. CISA gave US government agencies until 12 Aug 2025 to fix it.
  3. If it can’t be fixed, take it offline.CISA’s advice when there’s no fix is to stop using the product, or take it off the internet, until there is one.

You can’t fix someone else’s server, but you can watch for what follows a break-in like this: a breach notice, a password reset you didn’t ask for, or a scam message that knows things it shouldn’t. HARD watches for those for you and your family.

Timeline

DateEvent
The flaw is made public in the National Vulnerability Database, with a severity score of 9.8.[2]
CISA adds it to its catalog of flaws known to be used in attacks.[1]
CISA’s deadline for US government agencies to fix it.[1]
FIRST puts the odds of it being used in attacks in the next 30 days at 93%.[4]

See also

Other CrushFTP flaws

Similar flaws

  • CVE-2023-20198, Cisco IOS XE Web UI: privilege escalation ·

Added the same day

  • CVE-2025-6558, Chrome and other Chromium browsers: ANGLE and GPU improper input validation ·
  • CVE-2025-49706, Microsoft SharePoint: improper authentication ·
  • CVE-2025-49704, Microsoft SharePoint: code injection ·
  • CVE-2025-2776, SysAid On-Prem: on-prem improper restriction of XML external entity reference ·
  • CVE-2025-2775, SysAid On-Prem: on-prem improper restriction of XML external entity reference ·

Every CrushFTP flaw on CISA’s list · Everything added in July 2025

References

  1. ^ Cybersecurity and Infrastructure Security Agency. “CrushFTP Unprotected Alternate Channel Vulnerability”. Known Exploited Vulnerabilities Catalog, added 22 Jul 2025.
  2. ^ National Institute of Standards and Technology. “CVE-2025-54309 Detail”. National Vulnerability Database, published 18 Jul 2025.
  3. ^ CrushFTP. Advisories and fixes: crushftp.com.
  4. ^ FIRST. “Exploit Prediction Scoring System”. EPSS 0.935, percentile 99.8, 31 Oct 2026.
  5. CVE Program. “CVE-2025-54309”. The official CVE record.

This article is built from CISA’s catalog (version 2026.10.30), NVD’s record and FIRST’s scores, kept in HARD’s database and checked every morning. The plain English is HARD’s.