Apache Tomcat Native: Initialization of a Resource with an Insecure Default
CVE-2026-86246 is a critical-severity initialization of a resource with an insecure default vulnerability in Apache Tomcat Native from Apache, with a CVSS 3.1 base score of 9.1 out of 10. It can be exploited remotely over the network by an unauthenticated attacker, without any action from a user. Affected Apache Tomcat Native versions: 2.0.0 through 2.0.15; 1.3.0 through 1.3.8. The record does not name a fixed version, so check the vendor advisory. There is no confirmed exploitation so far. EPSS estimates a 0.35% chance of exploitation within 30 days, which is low compared with other CVEs.
Critical severity: a successful attack would have severe impact.
What to do
- Update Tomcat Native to 1.3.9 or 2.0.16, whichever matches your release line, or a later version.
- Read the advisory on lists.apache.org for workarounds and exact fixed builds.
- Until you can update, restrict network access to the affected service so it is not reachable from untrusted networks.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Apache | Apache Tomcat Native | 2.0.0 through 2.0.15; 1.3.0 through 1.3.8 | Not stated |
| Apache | Tomcat Native | 1.3.0 up to, but not including, 1.3.9; 2.0.0 up to, but not including, 2.0.16 | 1.3.9, 2.0.16 |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- NetworkCan be exploited remotely over a network, including the internet.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- NoneAvailability is not affected.
Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N. Scored by CISA (ADP).
Official description
Initialization of a resource with an insecure default vulnerability in Apache Tomcat Native enabled insecure options by default including ALLOW_CLIENT_RENEGOTIATION, NO_EXTENDED_MASTER_SECRET, IGNORE_UNEXPECTED_EOF and ALLOW_NO_DHE_KEX. This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Earlier unsupported versions may also be affected. Users are recommended to upgrade to version 2.0.16 or 1.3.9, which fix the issue.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Initialization of a Resource with an Insecure Default
The product initializes or sets a resource with a default that is intended to be changed by the product's installer, administrator, or maintainer, but the default is not secure.
More Initialization of a Resource with an Insecure Default vulnerabilities (CWE-1188)
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- openwall.com/lists/oss-security/2026/09/23/32Mailing List, Third Party Advisory
Other vulnerabilities in Apache Tomcat Native
- 7.4 High severity
- 7.5 High severity
- 9.1 Critical severity
- 7.5 High severity
Recent Initialization of a Resource with an Insecure Default vulnerabilities
- 9.1 Critical severity
- 10.0 Critical severity
- 7.5 High severity
- 8.6 High severity
- 9.1 Critical severity
- 9.5 Critical severity
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