Quick answers
- Is CVE-2026-49939 exploited in the wild?
- No. Junglewise Threat Intelligence has no report of CVE-2026-49939 being exploited in the wild.
- How severe is CVE-2026-49939?
- Informational severity, published 6 November 2026.
- Which products and versions are affected?
- Apache James prior to 3.9.1.
- Is there a fix for CVE-2026-49939?
- Yes: fixed in 3.9.1. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.
- How is CVE-2026-49939 attacked?
- It is attacked over the network, in a hosted service.
- Am I affected by CVE-2026-49939?
- Check whether you run Apache James 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.
How to fix
- Fixed in: 3.9.1
Technical details
The vulnerability is an access control bypass in Apache James' ACL processing between the JMAP and IMAP protocols. The JMAP protocol fails to properly account for negative ACL rules set by IMAP, allowing authenticated users to bypass folder administration restrictions. An attacker with a James account can perform unauthorized folder operations by switching between IMAP and JMAP protocols.
Affected products
- Apache James prior to 3.9.1
Timeline
- 2026-11-06: disclosed