CVE-2026-43515: Improper Authorization vulnerability when multiple method constraints define an HTTP method for the same exten

Q: How do I fix CVE-2026-43515?

tomcat: upgrade to 9.0.118, 10.1.55, 11.0.22. Exact commands for each OS are on this page.

Q: Is CVE-2026-43515 being exploited?

CVE-2026-43515 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2026-43515 affect?

CVE-2026-43515 affects tomcat. Severity is critical (CVSS 9.1). Improper Authorization vulnerability when multiple method constraints define an HTTP method for the same extension in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0

Q: How urgent is CVE-2026-43515?

Priority 62/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

This week

CRITICAL 9.1REMOTEWATCHLISTUPGRADE

CVE-2026-43515 is a critical-severity flaw (CVSS 9.1) affecting tomcat. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Improper Authorization vulnerability when multiple method constraints define an HTTP method for the same extension in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0.0.M1 through 9.0.117, from 8.5.0 through 8.5.100, from 7.0.0 through 7.0.109. Users are recommended to upgrade to version 11.0.22, 10.1.55 or 9.0.118 which fix the issue.

Why this priority

Critical severity
CISA SSVC: automatable with total technical impact
Remotely exploitable, no login, no user action
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	9.1 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	1.2% (top 31%)
CISA exploited list	No
Weakness	CWE-285
Published	2026-05-12
Last modified	2026-10-26

Publisher (CNA): Apache Software Foundation · Vendor: apache

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-05-12 16:16 UTCPublished CVE record published
2026-10-26 18:10 UTCUpdated Record last modified

apache tomcat UPGRADE

Affected: >= 7.0.0 and <= 7.0.109 · >= 8.5.0 and <= 8.5.100 · >= 9.0.0 and < 9.0.118 · >= 10.1.0 and < 10.1.55 · >= 11.0.0 and < 11.0.22

Fixed in: 9.0.118, 10.1.55, 11.0.22

Safe to downgrade to: a release before 7.0.0

1. Check installed version

apt-cache policy tomcat || rpm -q tomcat || tomcat --version

2. UPGRADE to 9.0.118 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade tomcat

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tomcat

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

3. If no update is available yet, DOWNGRADE to a release before 7.0.0 (Debian / Ubuntu)

apt-cache madison tomcat sudo apt install tomcat=<VERSION_BEFORE_7.0.0> sudo apt-mark hold tomcat

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list tomcat sudo dnf downgrade tomcat-<VERSION_BEFORE_7.0.0> sudo dnf versionlock add tomcat

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Exact fixes by distribution

Maven · org.apache.tomcat.embed:tomcat-embed-core · FIXED · 9.0.118 · vulnerable: < 9.0.118 · source

Set org.apache.tomcat.embed:tomcat-embed-core to 9.0.118 or later in pom.xml or build.gradle, then rebuild and redeploy.

Maven · org.apache.tomcat:tomcat · FIXED · 9.0.118 · vulnerable: < 9.0.118 · source

Set org.apache.tomcat:tomcat to 9.0.118 or later in pom.xml or build.gradle, then rebuild and redeploy.

Fedora ELN · xfsdump · FIXED · 3.3.0-3.eln159 · FEDORA-2026-6e9bb3f901 · source

sudo dnf upgrade --advisory=FEDORA-2026-6e9bb3f901

Fedora 46 · fio · FIXED · 3.43-2.fc46 · FEDORA-2026-b36219886b · source

sudo dnf upgrade --advisory=FEDORA-2026-b36219886b

Debian 12 · tomcat10 · FIXED · 10.1.55-1~deb12u1

sudo apt update && sudo apt install --only-upgrade tomcat10 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' tomcat10)" ge "10.1.55-1~deb12u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · tomcat10 · FIXED · 10.1.55-1~deb13u1

sudo apt update && sudo apt install --only-upgrade tomcat10 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' tomcat10)" ge "10.1.55-1~deb13u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 13 · tomcat11 · FIXED · 11.0.22-1~deb13u1

sudo apt update && sudo apt install --only-upgrade tomcat11 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' tomcat11)" ge "11.0.22-1~deb13u1" && echo PATCHED || echo STILL-VULNERABLE

Debian 12 · tomcat9 · FIXED · 9.0.70-2

sudo apt update && sudo apt install --only-upgrade tomcat9 dpkg --compare-versions "$(dpkg-query -W -f='${Version}' tomcat9)" ge "9.0.70-2" && echo PATCHED || echo STILL-VULNERABLE

RHEL 10 · tomcat9 · FIXED · tomcat9-9.0.120-1.el10_2

sudo dnf upgrade --advisory=RHSA-2026:68651 rpm -q tomcat9

RHEL 10 · tomcat · FIXED · tomcat-10.1.49-4.el10_2

sudo dnf upgrade --advisory=RHSA-2026:69259 rpm -q tomcat

RHEL 10.0 Extended Update Support · tomcat9 · FIXED · tomcat9-9.0.120-1.el10_0

sudo dnf upgrade --advisory=RHSA-2026:67163 rpm -q tomcat9

RHEL 10.0 Extended Update Support · tomcat · FIXED · tomcat-10.1.49-1.el10_0

sudo dnf upgrade --advisory=RHSA-2026:67164 rpm -q tomcat

RHEL 8 · tomcat · FIXED · tomcat-9.0.120-1.el8_10

sudo dnf upgrade --advisory=RHSA-2026:68677 rpm -q tomcat

Amazon Linux 2023 · see advisory · FIXED · ALAS2023-2026-1776 · source

sudo dnf update --advisory=ALAS2023-2026-1776

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

GitHub PoC: covepseng/cve-2026-43515-poc (1 stars)

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2026-43515?

tomcat: upgrade to 9.0.118, 10.1.55, 11.0.22. Exact commands for each OS are on this page.

Is CVE-2026-43515 being exploited?

CVE-2026-43515 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2026-43515 affect?

CVE-2026-43515 affects tomcat. Severity is critical (CVSS 9.1). Improper Authorization vulnerability when multiple method constraints define an HTTP method for the same extension in Apache Tomcat. This issue affects Apache Tomcat: from 11.0.0-M1 through 11.0.21, from 10.1.0-M1 through 10.1.54, from 9.0

How urgent is CVE-2026-43515?

Priority 62/100. Critical severity; CISA SSVC: automatable with total technical impact; Remotely exploitable, no login, no user action; On your watchlist

Software pages

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References

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