CVE-2026-123306: JetBrains IntelliJ IDEA · Improper Certificate Validation
Affects JetBrains IntelliJ IDEASource CVE Database V5
Not known to be exploited · CVSS 7.4 High : upgrade to 2026.3 soon.
Data as of 6 Nov 2026, 11:02 UTC
Thin evidence
One scorer or none| CNA (JetBrains) | CVSS 3.1 | 7.4 |
|---|
- Patch
- Available – fixed in 2026.3
CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:NExploitation evidence
Disclosed: evidence found.
CVE published 6 Nov 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors
A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 5 Nov 2026.
What to do
Upgrade JetBrains IntelliJ IDEA to 2026.3.
Affected software
| Product | Affected | Fixed in |
|---|---|---|
| JetBrainsIntelliJ IDEA | Affected
| Fixed in
|
AI-suggested
Upgrade IntelliJ IDEA to version 2026.3 or later, where this improper certificate validation issue has been fixed. No other mitigation is necessary as the vendor has provided an official fix.
Description
CVE-2026-123306 is a high-severity vulnerability in JetBrains IntelliJ IDEA before version 2026.3. It involves improper certificate validation that allows server certificates to be added to the trust store during headless runs. This flaw could enable an attacker to impersonate trusted servers, potentially leading to unauthorized access or data interception.