Critical Acronis Backup Vulnerability CVE-2026-87886: SMBs Must Act Fast

CVE-2026-87886 in Acronis Backup is being exploited in the wild, and SMBs must take immediate action.

The short version

CVE-2026-87886 is a permissions flaw in Acronis Backup that allows unauthorized access.
SMBs using Acronis Backup should update immediately to patch the vulnerability.
Check your systems for signs of compromise if you haven't updated yet.
Darksteel can help assess your exposure and secure your backups.

What is CVE-2026-87886 in Acronis Backup?

CVE-2026-87886 is a vulnerability in Acronis Backup, a widely used backup and recovery software. The flaw stems from incorrect default permissions in the software, which can allow attackers to gain unauthorized access to systems where Acronis Backup is installed.

This vulnerability is serious because it could allow attackers to bypass security controls and access systems where Acronis is configured. The flaw has been confirmed as exploited in the wild, which means attackers are already using it to target vulnerable systems.

The U.S. Cybersecurity and Infrastructure Security Agency (CISA) added this flaw to its Known Exploited Vulnerabilities (KEV) list on September 16, 2026, signaling that it is actively being used in real-world attacks.

How Does This Affect SMBs?

If your SMB uses Acronis Backup, you are at risk if you haven’t applied the latest security updates. This vulnerability could be exploited by attackers to access your systems or sensitive data.

Because Acronis Backup is often used to manage critical business data, an attacker who gains access could potentially access or manipulate backups, which could disrupt your operations or lead to data loss.

SMBs should treat this vulnerability with urgency, as attackers may already be targeting systems with incorrect permissions.

What Should You Do This Week?

First, determine whether your organization is using Acronis Backup. If you are, check the version you’re running. The vulnerability affects versions prior to the latest security update.

Apply the vendor’s patch as soon as possible. Acronis has released an update to address this issue, and the U.S. government has given federal agencies until September 19, 2026, to remediate. While this is a federal deadline, SMBs should act just as quickly.

If you're unsure how to apply the patch or need help identifying affected systems, reach out to your IT team or a trusted cybersecurity provider like Darksteel Technologies for assistance.

How Can You Tell If You’ve Already Been Hit?

Detecting whether your systems have been compromised by this vulnerability can be difficult, especially if you don’t have robust monitoring in place. However, there are some signs to watch for.

Unusual activity in your Acronis Backup logs, such as unexpected login attempts or changes to backup configurations, may indicate an intrusion. You should also look for any unauthorized access to sensitive data or systems.

If you suspect your systems have been compromised, stop using the affected systems immediately and contact a cybersecurity professional for a full assessment.

Not sure whether your environment is exposed? That is exactly what our Vulnerability Management service is built to surface. Talk to us.

Frequently asked questions

Is my business at risk if we don’t use Acronis Backup?

If your business does not use Acronis Backup, then you are not directly at risk from this specific vulnerability. However, it’s still important to maintain good cybersecurity hygiene and ensure all software is up to date.

What if I can’t update right away?

If you are unable to apply the patch immediately, consider implementing additional protective measures, such as restricting access to the Acronis Backup system and monitoring for unusual activity. Contact a cybersecurity expert to help you assess your risks.

How can I check if I’m using a vulnerable version of Acronis Backup?

Review the version number of your Acronis Backup software. If it is older than the version that includes the security patch, your system is vulnerable. You can find the latest version information on the Acronis website or by contacting their support team.

Can this vulnerability lead to a ransomware attack?

There is currently no confirmed evidence that this vulnerability has been used in a ransomware attack. However, because it allows unauthorized access, it could be used as a stepping stone for other attacks. That’s why it’s critical to patch now to prevent any potential damage.

Source (public domain): CISA