CVE-2026-86246: Initialization of a resource with an insecure default vulnerability in Apache Tomcat Native enabled insecure o

This month

CRITICAL 9.1REMOTEWATCHLISTUPGRADE

CVE-2026-86246 is a critical-severity flaw (CVSS 9.1) affecting tomcat native. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Initialization of a resource with an insecure default vulnerability in Apache Tomcat Native enabled insecure options by default including ALLOW_CLIENT_RENEGOTIATION, NO_EXTENDED_MASTER_SECRET, IGNORE_UNEXPECTED_EOF and ALLOW_NO_DHE_KEX. This issue affects Apache Tomcat Native: from 2.0.0 through 2.0.15, from 1.3.0 through 1.3.8. Earlier unsupported versions may also be affected. Users are recommended to upgrade to version 2.0.16 or 1.3.9,

Why this priority

Critical severity
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	0.3% (top 72%)
CISA exploited list	No
Weakness	CWE-1188
Published	2026-09-23
Last modified	2026-10-06

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

Last updated 2026-10-06 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-09-23 13:17 UTCPublished CVE record published
2026-10-06 13:50 UTCUpdated Record last modified

apache tomcat native UPGRADE

Affected: >= 1.3.0 and < 1.3.9 · >= 2.0.0 and < 2.0.16

Fixed in: 1.3.9, 2.0.16

Safe to downgrade to: a release before 1.3.0

1. Check installed version

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

2. UPGRADE to 1.3.9 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade tomcat-native

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 1.3.0 (Debian / Ubuntu)

apt-cache madison tomcat-native sudo apt install tomcat-native=<VERSION_BEFORE_1.3.0> sudo apt-mark hold tomcat-native

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

dnf --showduplicates list tomcat-native sudo dnf downgrade tomcat-native-<VERSION_BEFORE_1.3.0> sudo dnf versionlock add tomcat-native

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.

Advisories and coverage

Official advisories

Amazon Linux 2023 ALAS: ALAS2023-2026-3167 (important): tomcat-native 2026-10-12

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-2026-86246?

tomcat native: upgrade to 1.3.9, 2.0.16. Exact commands for each OS are on this page.

Is CVE-2026-86246 being exploited?

CVE-2026-86246 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-2026-86246 affect?

CVE-2026-86246 affects tomcat native. Severity is critical (CVSS 9.1). Initialization of a resource with an insecure default vulnerability in Apache Tomcat Native enabled insecure options by default including ALLOW_CLIENT_RENEGOTIATION, NO_EXTENDED_MASTER_SECRET, IGNORE_UNEXPECTED_EOF and ALLOW_NO_DHE_KEX.

How urgent is CVE-2026-86246?

Priority 49/100. Critical severity; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Apache Tomcat vulnerabilities

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References

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