Critical severity · published Oct 20, 2026
CVE-2026-103119
Apache Tomcat: AJP response mix-up
9.1
CVSS
0.6%
EPSS
No
On KEV
Description
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:N/A:H
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
High
Integrity
None
Availability
High
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.6% · higher than 48% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
TO
Tomcat · Apache
11.0.0-M25 through 11.0.26 · source: vendor
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-103119
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-103119
lists.apache.org
https://lists.apache.org/thread.html/sk2cg4k077fwcqbm6tqz2n700nq06h80
www.openwall.com
http://www.openwall.com/lists/oss-security/2026/10/20/28
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