CVE-2026-26240: A buffer overflow vulnerability has been reported to affect File Station 5

This month

CRITICAL 9.1REMOTEUPGRADE

CVE-2026-26240 is a critical-severity flaw (CVSS 9.1) affecting file station. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A buffer overflow vulnerability has been reported to affect File Station 5. The remote attackers can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: File Station 5 5.5.6.5243 and later

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.4% (top 62%)
CISA exploited list	No
Weakness	CWE-121
Published	2026-06-10
Last modified	2026-07-23

Publisher (CNA): QNAP Systems, Inc. · Vendor: qnap

Last updated 2026-07-23 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-06-10 05:16 UTCPublished CVE record published
2026-07-23 09:10 UTCUpdated Record last modified

qnap file station UPGRADE

Affected: >= 5.5.6.4691 and < 5.5.6.5243

Fixed in: 5.5.6.5243

Safe to downgrade to: a release before 5.5.6.4691

1. Check installed version

apt-cache policy file-station || rpm -q file-station || file-station --version

2. UPGRADE to 5.5.6.5243 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade file-station

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade file-station

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 5.5.6.4691 (Debian / Ubuntu)

apt-cache madison file-station sudo apt install file-station=<VERSION_BEFORE_5.5.6.4691> sudo apt-mark hold file-station

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list file-station sudo dnf downgrade file-station-<VERSION_BEFORE_5.5.6.4691> sudo dnf versionlock add file-station

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-26240?

file station: upgrade to 5.5.6.5243. Exact commands for each OS are on this page.

Is CVE-2026-26240 being exploited?

CVE-2026-26240 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-26240 affect?

CVE-2026-26240 affects file station. Severity is critical (CVSS 9.1). A buffer overflow vulnerability has been reported to affect File Station 5. The remote attackers can then exploit the vulnerability to modify memory or crash processes. We have already fixed the vulnerability in the following version: File

How urgent is CVE-2026-26240?

Priority 46/100. Critical severity; Remotely exploitable, no login, no user action

Software pages

QNAP vulnerabilities

Related CVEs

CVE-2026-24721 MEDIUM 6.5 UPGRADE A NULL pointer dereference vulnerability has been reported to affect File Station 5
CVE-2026-24722 MEDIUM 6.5 UPGRADE A NULL pointer dereference vulnerability has been reported to affect File Station 5
CVE-2026-24723 MEDIUM 6.5 UPGRADE A NULL pointer dereference vulnerability has been reported to affect File Station 5
CVE-2026-26241 CRITICAL 9.1 UPGRADE A buffer overflow vulnerability has been reported to affect File Station 5
CVE-2026-26239 HIGH 8.1 UPGRADE A buffer overflow vulnerability has been reported to affect File Station 5

References

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