Quick answers
- Is CVE-2026-115786 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-115786 being exploited in the wild.
- How severe is CVE-2026-115786?
- Medium severity, with a CVSS score of 6.5, published 23 October 2026.
- Which products and versions are affected?
- Zimbra Collaboration Suite 10.1.16, 10.1.20.
- Is there a fix for CVE-2026-115786?
- 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-2026-115786 attacked?
- It is attacked over the network.
- Am I affected by CVE-2026-115786?
- Check whether you run 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
The vulnerability is a quota-accounting logic error in document sharing: when a document is shared with a recipient, the document size is charged to the recipient's mailbox quota, but when the share is revoked, the mailbox-wide quota charge is not reversed while folder counters are. An authenticated user can repeatedly share and revoke a document to an arbitrary target, causing the quota to accumulate charges without leaving visible shared-file records. This allows denial of service against any user's mailbox on systems with finite quotas.
Affected products
- Zimbra Collaboration Suite 10.1.16, 10.1.20
Timeline
- 2026-10-23: disclosed