# CVE-2026-123848: JetBrains IntelliJ IDEA TLS hostname verification missing

Source: https://junglewise.ai/threats/cve-2026-123848-in-jetbrains-intellij-idea-before-2026-3-host-name-verification  
Publisher: Junglewise Threat Intelligence, https://junglewise.ai/threats  
Published: 2026-11-06. Updated: 2026-11-06  
License: CC BY 4.0 with a link back

CVE-2026-123848 · Severity: high · CVSS 7.4 · Published 2026-11-06

IntelliJ IDEA, a code editor used by software developers, failed to verify that TLS certificates matched the server hostname when connecting to remote servers. An attacker positioned to intercept network traffic could use a valid certificate for a different domain to impersonate legitimate servers and intercept sensitive communications, credentials, or code.

Technologies: [Jetbrains IntelliJ IDEA](https://junglewise.ai/threats/technologies/intellij-idea). Vendors: [Jetbrains](https://junglewise.ai/threats/vendors/jetbrains).

## Quick answers

**Is CVE-2026-123848 exploited in the wild?** No. Junglewise Threat Intelligence has no report of CVE-2026-123848 being exploited in the wild.

**How severe is CVE-2026-123848?** High severity, with a CVSS score of 7.4, published 6 November 2026.

**Which products and versions are affected?** Jetbrains IntelliJ IDEA before 2026.3.

**Is there a fix for CVE-2026-123848?** Yes: fixed in IntelliJ IDEA 2026.3. Junglewise finds every place you run it, drafts the upgrade and applies it once you approve.

**How is CVE-2026-123848 attacked?** It is attacked over the network, in a web application.

**Am I affected by CVE-2026-123848?** Check whether you run Jetbrains IntelliJ IDEA 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 IntelliJ IDEA 2026.3

## Technical details

The vulnerability is a missing hostname verification in TLS certificate validation. When IntelliJ IDEA connects to servers, it did not verify that the certificate's Common Name or Subject Alternative Name matched the requested hostname, allowing any valid certificate to be accepted. This affects certificate-based authentication and secure connections, exploitable via man-in-the-middle attacks on network connections to remote servers.

## Affected products

- JetBrains IntelliJ IDEA before 2026.3

## Timeline

- 2026-11-06: disclosed

## References

- [https://www.jetbrains.com/privacy-security/issues-fixed/](https://www.jetbrains.com/privacy-security/issues-fixed/)

## Related threats

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- [JetBrains IntelliJ IDEA code execution via Terraform File Watchers](https://junglewise.ai/threats/cve-2026-123849-in-jetbrains-intellij-idea-before-2026-3-code-execution-was)
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