---
title: "CVE-2026-103119: Apache Tomcat - Buffer Overflow"
description: "Apache Tomcat 11.0.0-M25 through 11.0.26 contains a buffer under-read caused by improper handling of large non-blocking writes, letting attackers cause request failures and possible data leakage between responses, exploit requires crafted requests on the same connection."
url: https://panop.io/threat-heartbeat/CVE-2026-103119/
---

# CVE-2026-103119 Apache Tomcat - Buffer Overflow

Apache Tomcat 11.0.0-M25 through 11.0.26 contains a buffer under-read caused by improper handling of large non-blocking writes, letting attackers cause request failures and possible data leakage between responses, exploit requires crafted requests on the same connection.

CVSS base score 9.1 /10

Critical

CISA KEV

Not listed

Public exploit

None known

Authentication

Not required

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-103119)

## Details

Type

Buffer Overflow

Impact

Information Disclosure, Denial Of Service

CVSS vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H

Published

20 October 2026

Updated

21 October 2026

Weakness

[CWE-127](https://cwe.mitre.org/data/definitions/127.html)

## Vendor fix

Upgrade to version 11.0.27.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-103119](https://nvd.nist.gov/vuln/detail/CVE-2026-103119)
- [https://lists.apache.org/thread.html/sk2cg4k077fwcqbm6tqz2n700nq06h80](https://lists.apache.org/thread.html/sk2cg4k077fwcqbm6tqz2n700nq06h80)
- [http://www.openwall.com/lists/oss-security/2026/10/20/28](http://www.openwall.com/lists/oss-security/2026/10/20/28)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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