CVE-2026-78437
published 2026-09-23CVE-2026-78437: Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail…
PriorityP347high7.3CVSS 3.1
AVNACLPRNUINSUCLILAL
EPSS
0.26%
16.7th percentile
Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
Affected
6 ranges
| Vendor | Product | Version range | Fixed in |
|---|---|---|---|
| apache | tomcat | — | — |
| apache_software_foundation | apache_tomcat | 10.1.53 – 10.1.59 | — |
| apache_software_foundation | apache_tomcat | 11.0.19 – 11.0.25 | — |
| apache_software_foundation | apache_tomcat | 9.0.116 – 9.0.121 | — |
| debian | tomcat9 | — | — |
| pki-deps_10.6 | pki-servlet-engine | — | — |
CVSS provenance
nvdv3.17.3HIGHCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L
vendor_redhat7.3HIGH
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Red Hat
tomcat: Apache Tomcat: Denial of Service via malformed HTTP/2 request
vendor_redhat·2026-09-23·CVSS 7.3
CVE-2026-78437 [HIGH] CWE-459 tomcat: Apache Tomcat: Denial of Service via malformed HTTP/2 request
tomcat: Apache Tomcat: Denial of Service via malformed HTTP/2 request
Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
A flaw was found in Apache Tomcat. An incomplete cleanup vulnerability allows a remote attacker to send a malformed HTTP/2 request. This can potentially cause a denial of service, leading to one request from another user failing.
Package: tomcat (Red Hat Enterprise Linux 10) - Under investigation
Package: tomcat9 (Red Hat Enterprise Linux 10) - Unde
GHSA
Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
ghsa_unreviewed·2026-09-23
CVE-2026-78437 CWE-459 Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
No detection rules found.
No public exploits indexed.
Hackernews
⚡ Weekly Recap: NetScaler and FortiMail 0-Days, AI Coding Leaks, Spectre v2 and Ransomware Arrests
blogs_hackernews·2026-10-05·CVSS 7.5
CVE-2026-88779 [HIGH] ⚡ Weekly Recap: NetScaler and FortiMail 0-Days, AI Coding Leaks, Spectre v2 and Ransomware Arrests
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## ⚡ Weekly Recap: NetScaler and FortiMail 0-Days, AI Coding Leaks, Spectre v2 and Ransomware Arrests
A blank field. A public repo. One reply to an email. A box left exposed. None of this sounds dramatic, which is partly the problem. This week’s threats keep finding leverage in small things that were easy to overlook.
There are actively exploited bugs in the mix, cleaner intrusion paths, smarter automation, and a long patch list waiting behind them. Some attacks are getting more capable. Others are still getting in because the basics gave way first.
Here’s what mattered this week.
## ⚡ Threat of the Week
Citrix Warns of Ne
Bugzilla
CVE-2026-73581 CVE-2026-75973 CVE-2026-76183 CVE-2026-77756 CVE-2026-77762 CVE-2026-77791 CVE-2026-78383 CVE-2026-78437 CVE-2026-79677 CVE-2026-86248 CVE-2026-86350 CVE-2026-87022 tomcat: various flaw
bugzilla·2026-09-29·CVSS 9.8
CVE-2026-73581 [CRITICAL] CVE-2026-73581 CVE-2026-75973 CVE-2026-76183 CVE-2026-77756 CVE-2026-77762 CVE-2026-77791 CVE-2026-78383 CVE-2026-78437 CVE-2026-79677 CVE-2026-86248 CVE-2026-86350 CVE-2026-87022 tomcat: various flaw
CVE-2026-73581 CVE-2026-75973 CVE-2026-76183 CVE-2026-77756 CVE-2026-77762 CVE-2026-77791 CVE-2026-78383 CVE-2026-78437 CVE-2026-79677 CVE-2026-86248 CVE-2026-86350 CVE-2026-87022 tomcat: various flaws [fedora-all]
Disclaimer: Community trackers are created by Red Hat Product Security team on a best effort basis. Package maintainers are required to ascertain if the flaw indeed affects their package, before starting the update process.
Improper handling of length parameter inconsistency vulnerability in Apache Tomcat allows WebSocket message smuggling when per-message-deflate is used.
This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.25, from 10.1.0-M1 through 10.1.59, from 9.0.0.M1 through 9.0.121.
The following versions were EOS at the time the CVE was created but are kn
Bugzilla
CVE-2026-78437 tomcat: Apache Tomcat: Denial of Service via malformed HTTP/2 request
bugzilla·2026-09-23·CVSS 7.3
CVE-2026-78437 [HIGH] CVE-2026-78437 tomcat: Apache Tomcat: Denial of Service via malformed HTTP/2 request
CVE-2026-78437 tomcat: Apache Tomcat: Denial of Service via malformed HTTP/2 request
Incomplete cleanup vulnerability in Apache Tomcat allows a malformed request to potentially (depends on timing) cause one request from another user to fail.
This issue affects Apache Tomcat: from 11.0.19 through 11.0.25, from 10.1.53 through 10.1.59, from 9.0.116 through 9.0.121.
Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.
2026-09-23
Published