What is CVE-2026-50055?
A policy-enforcement flaw in Zimbra Collaboration Suite allows an authenticated user to bypass disabled mail forwarding by using a Sieve notify action to send copies of email content and headers to an arbitrary address.
The record classifies CVE-2026-50055 under weakness class CWE-863. Its CVSS v3 base vector states that the flaw is reachable remotely over the network, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 4 days ago.
Severity and exploitation probability
- CVSS v3.1 base score
- 6.5 — MEDIUM
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:N - EPSS (FIRST)
- 0.2% probability of exploitation in the next 30 days, higher than 18.2% of all scored CVEs
- CISA KEV
- Not listed in the CISA Known Exploited Vulnerabilities catalog
- Threadlinqs priority
- 6/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
- Published
- 2026-10-08
Is CVE-2026-50055 being exploited?
Weaponised exploit code for CVE-2026-50055 is publicly available. 1 public proof-of-concept repository is tracked for this identifier. It currently carries a trending score of 47 in the Threadlinqs vulnerability feed.
- HORKimhab/CVE-2026-50055 (github)
Affected products and versions
- Zimbra: Collaboration Suite
How to fix CVE-2026-50055
No vendor patch reference has been recorded for CVE-2026-50055 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.
Threat activity tracking CVE-2026-50055
1 tracked threat in the Threadlinqs corpus references CVE-2026-50055, either in the campaign’s CVE list or as an indicator on the campaign record.
Sources
Enriched from CVE.org, FIRST EPSS, public proof-of-concept repositories. Last verified by Threadlinqs on .