CVE-2015-9256: Datto ALTO and SIRIS devices allow remote attackers to obtain sensitive information via access to device/VM re

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MEDIUM 5.3REMOTEMITIGATEMITIGATEMITIGATE

CVE-2015-9256 is a medium-severity flaw (CVSS 5.3) affecting alto 3 firmware, alto 2 firmware, alto xl firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Datto ALTO and SIRIS devices allow remote attackers to obtain sensitive information via access to device/VM restore mount points, because they do not have ACLs by default.

Why this priority

Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.3 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.0% (top 36%)
CISA exploited list	No
Weakness	CWE-200
Published	2018-02-20
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: datto

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2018-02-20 06:29 UTCPublished CVE record published
2026-06-17 00:36 UTCUpdated Record last modified

datto alto 3 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

datto alto 2 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

datto alto xl firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

datto siris 3 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

datto siris 2 firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

datto siris 3 x all-flash firmware MITIGATE

Affected: all versions

Fixed in: no fixed release known

Safe to downgrade to: no unaffected older release

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

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-2015-9256?

alto 3 firmware: mitigate or apply the listed mitigation; alto 2 firmware: mitigate or apply the listed mitigation; alto xl firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2015-9256 being exploited?

CVE-2015-9256 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-2015-9256 affect?

CVE-2015-9256 affects alto 3 firmware, alto 2 firmware, alto xl firmware. Severity is medium (CVSS 5.3). Datto ALTO and SIRIS devices allow remote attackers to obtain sensitive information via access to device/VM restore mount points, because they do not have ACLs by default.

How urgent is CVE-2015-9256?

Priority 40/100. Remotely exploitable, no login, no user action

Related CVEs

CVE-2015-9255 MEDIUM 5.3 MITIGATE MITIGATE Datto ALTO and SIRIS devices allow remote attackers to obtain sensitive information about data, software versi
CVE-2015-9254 CRITICAL 9.8 MITIGATE MITIGATE Datto ALTO and SIRIS devices have a default VNC password.
CVE-2015-2081 CRITICAL 9.8 MITIGATE MITIGATE Datto ALTO and SIRIS devices allow Remote Code Execution via unauthenticated requests to PHP scripts.

References

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