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CVE-2026-76183· NVD / CVE Program· CNA apache

Apache Tomcat: Bypass of security constraints for WebSocket endpoints

Noroxi assessment

Priority: Monitor (action score 39/100)

  • Public proof-of-concept code exists (GitHub); there is no record of exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.39% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: Apache Software Foundation Apache Tomcat 11.0.26.

Low priority for now. Upgrade to Apache Software Foundation Apache Tomcat 11.0.26 or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Authentication Bypass by Alternate Name vulnerability in Apache Tomcat allowed the security constraints for any WebSocket endpoint to be bypassed. 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 known to be affected: from 8.5.0 through 8.5.100, from 7.0.43 through 7.0.109. Other unsupported versions may also be affected. Users are recommended to upgrade to version 11.0.26, 10.1.60 or 9.0.122, which fix the issue.

CriticalCVSS 9.8 · v3.1—Proof of concept Fix available
Published
Sep 23, 2026
Updated
Sep 30, 2026
EPSS
0.3% · 31th percentile

Report tools

JSON

Action score

39

Monitor

Low priority for now.

CVSS
39 / 40 · 9.8 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.3%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
total

Vulnrichment: CISA's decision-tree inputs.

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • Proof of concept exists, no weaponized module
  • A fix has been released

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2026-76183

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (apache). Independent of NVD's CPE analysis and usually ahead of it.

  • Apache Software Foundation Apache Tomcat

    • 11.0.0-M1 and later · up to and including 11.0.25affected · semver
    • 10.1.0-M1 and later · up to and including 10.1.59affected · semver
    • 9.0.0.M1 and later · up to and including 9.0.121affected · semver
    • 8.5.0 and later · up to and including 8.5.100affected · semver
    • 7.0.43 and later · up to and including 7.0.109affected · semver
    • before 7.0.43not affected · semver

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Debian:12tomcat10from 0—
Debian:12tomcat9before 9.0.70-29.0.70-2
Debian:13tomcat11from 0—
Debian:14tomcat10before 10.1.60-110.1.60-1
openSUSE:Leap 16.0libtcnative-1-0before 1.3.9-160000.1.11.3.9-160000.1.1
openSUSE:Leap 16.0libtcnative-2-0before 2.0.16-160000.1.12.0.16-160000.1.1
openSUSE:Leap 16.0tomcatbefore 9.0.122-160000.1.19.0.122-160000.1.1
openSUSE:Leap 16.0tomcat10before 10.1.60-160000.1.110.1.60-160000.1.1
openSUSE:Leap 16.0tomcat11before 11.0.26-160000.1.111.0.26-160000.1.1
openSUSE:Tumbleweedtomcatbefore 9.0.122-1.19.0.122-1.1
openSUSE:Tumbleweedtomcat10before 10.1.60-1.110.1.60-1.1
openSUSE:Tumbleweedtomcat11before 11.0.26-1.111.0.26-1.1
Red Hat:hummingbird:1tomcat10before 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-admin-webappsbefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-commonbefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-docs-webappbefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-el-5.0-apibefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-jsp-3.1-apibefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-libbefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-servlet-6.0-apibefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-user-instancebefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat10-webappsbefore 0:10.1.60-0.1.hum10:10.1.60-0.1.hum1
Red Hat:hummingbird:1tomcat11before 0:11.0.26-0.1.hum10:11.0.26-0.1.hum1
Red Hat:hummingbird:1tomcat11-admin-webappsbefore 0:11.0.26-0.1.hum10:11.0.26-0.1.hum1

+18

Same product

apache software foundation: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-86248Apache Tomcat: Fix for CVE-2026-34500 was incomplete. OCSP checks sometimes soft-fail with FFM even when soft-fail is disabled
    39Monitor
  • CVE-2026-103119Apache Tomcat: AJP response mix-up
    36Monitor
  • CVE-2026-101356Apache Tomcat: HTTP/2 request/response mix-up after error during async processing
    36Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-87022Sep 23, 2026 · Apache Tomcat: WebSocket message smuggling with per-message-deflate
    30Monitor
  • ← EarlierCVE-2026-73581Sep 23, 2026 · Apache Tomcat: OpenSSL and OpenSSL-FFM TLS implementations ignore CRLs when certificate uses a keystore
    26Monitor
  • Later →CVE-2026-77762Sep 23, 2026 · Apache Tomcat: Stale HPACK emitter injects trailers into recycled pooled Request
    32Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Apache Software Foundation Apache Tomcat11.0.26 · descriptionVendor (CNA)
debian:tomcat1010.1.60-1 · Debian:14Package registry (OSV)
debian:tomcat99.0.70-2 · Debian:12Package registry (OSV)
opensuse:libtcnative-1-01.3.9-160000.1.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:libtcnative-2-02.0.16-160000.1.1 · openSUSE:Leap 16.0Package registry (OSV)
opensuse:tomcat9.0.122-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:tomcat1010.1.60-1.1 · openSUSE:TumbleweedPackage registry (OSV)
opensuse:tomcat1111.0.26-1.1 · openSUSE:TumbleweedPackage registry (OSV)
red hat:tomcat100:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-admin-webapps0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-common0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-docs-webapp0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-el-5.0-api0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-jsp-3.1-api0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-lib0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-servlet-6.0-api0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-user-instance0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat10-webapps0:10.1.60-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat110:11.0.26-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
red hat:tomcat11-admin-webapps0:11.0.26-0.1.hum1 · Red Hat:hummingbird:1Package registry (OSV)
suse:libtcnative-1-01.3.9-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:libtcnative-2-02.0.16-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:tomcat9.0.122-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:tomcat1010.1.60-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)
suse:tomcat1111.0.26-160000.1.1 · SUSE:Linux Enterprise Server 16.0Package registry (OSV)

Exploit status

Proof of concept available

A public proof of concept or detection signature exists. Exploit knowledge is out there; don't delay patching.

Evidence

  • Proof-of-concept repository on GitHub ×1

Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.

Public exploit evidence
SourceKindDate
Proof-of-concept repository on GitHubstars:12026-10-23

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

  1. Published
  2. First PoC+29 d
  3. TodayOct 24, 2026+31 d
EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Anyone who can reach it over the internet can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
high · data can be read
Integrity
high · data or configuration can be modified
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
High
Integrity impact
High
Availability impact
High

Weakness class (CWE)

CWE-289 · Authentication Bypass by Alternate Name

CVSS vector

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

nvd-secondary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Exploit maturitynone → poc
  2. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records