CVE-2026-42498 | Apache Tomcat: WebSocket authentication header exposure

Exposure of HTTP Authentication Header to unexpected hosts during WebSocket authentication vulnerability 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 9.0.2 through 9.0.117, from 8.5.24 through 8.5.100, from 7.0.83 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.

Published: 2026-05-12 Last update: 2026-06-17 Assigner: [email protected] Source: [email protected]
NVD Status：Analyzed，CVE State: published
View at NVD, CVE.org, EUVD

CVE-2026-42498 is rated Moderate Risk (44.2/100): CVSS High severity, with low exploitation likelihood (EPSS 0.55%). Review affected assets and schedule remediation.

Risk is dynamic; we continuously reassess and refresh what is shown on this page as upstream context changes.

Exploit prediction scoring system (EPSS) score for CVE-2026-42498

EPSS lead: Daily EPSS estimates relative likelihood of exploitation; percentile ranks this CVE among scored vulnerabilities (higher = more severe relative rank).

# Date Old EPSS score New EPSS score Delta (New - Old)
1 2026-06-15 0.05% 0.55% +0.50%
2 2026-05-14 0.03% 0.05% +0.03%
3 2026-05-13 — 0.03% —

Full EPSS history (3 records total)

Common vulnerability scoring system (CVSS) metrics for CVE-2026-42498

CVSS metrics for this CVE.

Base score Version Severity Vector Exploitability Impact Score source
7.3 3.1 HIGH
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:L/I:L/A:L Click to expand
Attack vector (AV:N)
Could be attacked over the internet or any normal routed network—not just someone sitting at the machine.
Attack complexity (AC:L)
Once they can reach the bug, pulling it off is straightforward—no weird race conditions or rare setup.
Privileges required (PR:N)
No account or special rights needed—anonymous or random user is enough.
User interaction (UI:N)
Nobody has to click “OK” or open a trap file; it can work without a victim helping.
Scope (S:U)
Damage stays in the same “trust bubble” as the broken component—no big spill into unrelated systems.
Confidentiality (C:L)
Some sensitive info could get out, but not a total data dump.
Integrity (I:L)
Attackers could change some data, but it’s limited—not everything goes.
Availability (A:L)
Might cause slowdowns, glitches, or partial disruption—not a full brick.
 3.9 3.4 134c704f-9b21-4f2e-91b3-4a467353bcc0

Weakness enumeration for CVE-2026-42498

GitHub Security Advisory for CVE-2026-42498

GHSA-fv25-8xcx-gqjc · Severity: high · Ecosystem: maven — Apache Tomcat - WebSocket authentication header exposure

OS Trackers for CVE-2026-42498

vendor priority summary link
debian not yet assigned CVE-2026-42498 not yet assigned priority: Debian including 3 source packages (tomcat10, tomcat11, tomcat9), 12 status rows across 5 suites (bookworm, bullseye, forky, sid, trixie): resolved 12. https://security-tracker.debian.org/tracker/CVE-2026-42498
suse medium — https://www.suse.com/security/cve/CVE-2026-42498/
ubuntu medium CVE-2026-42498 medium priority: Ubuntu including 6 source packages (tomcat10, tomcat11, tomcat6, tomcat7, tomcat8, tomcat9), 39 status rows across 9 suites (bionic, focal, jammy, noble, questing, resolute, trusty, upstream, xenial): needs-triage 19, DNE 15, ignored 5. https://ubuntu.com/security/CVE-2026-42498

Affected software / configurations for CVE-2026-42498

Vendor Product Version Raw CPE
apache tomcat >= 7.0.0, <= 7.0.109 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
apache tomcat >= 8.5.0, <= 8.5.100 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
apache tomcat >= 9.0.0, < 9.0.118 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
apache tomcat >= 10.1.0, < 10.1.55 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*
apache tomcat >= 11.0.0, < 11.0.22 cpe:2.3:a:apache:tomcat:*:*:*:*:*:*:*:*

References for CVE-2026-42498

cvelogic Threat Intelligence