Quick answers
- Is CVE-2026-73570 exploited in the wild?
- Yes. CVE-2026-73570 is known to be exploited in the wild, first recorded on 21 August 2026. Treat it as urgent.
- How severe is CVE-2026-73570?
- Critical severity, with a CVSS score of 9.8, published 21 August 2026.
- Which products and versions are affected?
- Zimbra Collaboration Suite <UNKNOWN>.
- Is there a fix for CVE-2026-73570?
- No fixed version is recorded yet. Check the vendor's advisory in the references below. If you run it, Junglewise drafts a mitigation that fits your setup and applies it once you approve, with senior security engineers behind it.
- How is CVE-2026-73570 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-73570?
- Check whether you run Synacor Zimbra Collaboration Suite (ZCS) or Zimbra Collaboration Suite at an affected version. Junglewise does that check for you around the clock: connect your code, cloud and domains, and it matches new vulnerabilities like this one against what you actually run and tells you when one reaches you.
Technical details
This is an OS command injection vulnerability in Zimbra Collaboration Suite's SMTP message processing component. An unauthenticated remote attacker can send specially crafted SMTP requests that inject operating system commands, leading to arbitrary command execution under the Zimbra service user context. The vulnerability requires no authentication and is reachable via the network on standard SMTP ports. Successful exploitation grants the attacker the ability to execute arbitrary system commands, potentially achieving full server compromise. The vulnerability is known to be actively exploited in the wild as of the disclosure date.
Affected products
- Zimbra Collaboration Suite <UNKNOWN>
Timeline
- 2026-08-21: disclosed
- 2026-08-21: exploited: actively exploited in the wild at time of disclosure