Critical-Severity Flaw in Apache Tomcat Tracked as CVE-2026-103119
A newly published critical vulnerability in Apache Tomcat carries a CVSS score of 9.1. Here is what is affected and how to respond.
Key points
- CVE-2026-103119 affects Apache Tomcat.
- CVSS 9.1 (Critical).
- No exploitation confirmed yet.
A critical security flaw tracked as CVE-2026-103119 has been published in the National Vulnerability Database for Apache Tomcat, with a CVSS base score of 9.1.
At a glance
- CVE
- CVE-2026-103119
- Product
- Apache Tomcat
- CVSS
- 9.1 Critical
- Weakness
- CWE-127
- Exploited
- No known exploitation
What is the vulnerability?
The NVD entry states: Buffer under-read vulnerability in Apache Tomcat meant that a large non-blocking write could result in the response body being split between the current request and the next request received on that connection leading most likely to failure of the second request and possibly leakage of data from the first response to the second.
This issue affects Apache Tomcat: from 11.0.0-M25 through 11.0.26.
Users are recommended to upgrade to version 11.0.27, which fixes the issue.
Affected versions
| Vendor | Product | Versions |
|---|---|---|
| Apache Software Foundation | Apache Tomcat | up to 11.0.26 |
CVSS vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H.
Is it being exploited?
There is no public confirmation of exploitation at the time of publication. It does not appear in CISA's Known Exploited Vulnerabilities catalog. We will update this report if that changes.
What should you do?
- Identify whether the affected product and versions run in your environment.
- Apply the vendor update listed in the advisory as soon as it is available.
- Limit network exposure of the affected service until it is patched.
- Monitor the vendor advisory for updated guidance or exploitation reports.
What to do and how to stay safe: CVE-2026-103119
- Vulnerability severity scores ignore your specific architecture and context.
- Exploitability depends on network exposure and user behavior, not just code flaws.
- Prioritization requires continuous asset inventory and threat intelligence alignment.
Risk-based vulnerability management focuses your limited resources on the flaws that actually threaten your business. Start by mapping your critical assets and checking for active exploits to prioritize your backlog.
Step-by-step guide: Risk-Based Vulnerability Management: Prioritize Fixes by Actual Danger
General security guidance from the Threat Times newsroom. It is not confirmed advice from the organisations named in this story.
Frequently asked questions
What is CVE-2026-103119?
CVE-2026-103119 is a CWE-127 vulnerability in Apache Tomcat.
How severe is CVE-2026-103119?
It has a CVSS score of 9.1 Critical.
Is CVE-2026-103119 being exploited?
There is no public confirmation of exploitation at the time of publication.
