A flaw was found in EAP's undertow http/1.1 chunked-transfer decoder. missing limits on size and count would allow an attacker to use an unauthenticated connection to drive the JVM to an OutOfMemory error, stopping all deployments on the listener, and achieving Denial of Service.
CVE-2026-15561
Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-08-11. A secondary CVSS source baseline 7.5; sources differ by 0.0.
- High severity, but no confirmed exploitation yet
A fix is available — apply it.
- CVSS v3
- 7.5
- EG Score
- 7.5HIGHmedium confidence
- EG Risk
- 49EG Risk 49/100CISA SSVC
EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).
How it’s computedSeverity75% × 45%Exploitation0% × 40%Automatability100% × 15%CISA SSVC: Track at low or medium mission impact; Attend at high (mission-essential systems).Action: A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.5%
- EPSS %ILE
- 37th
- KEV
- Not listed
CISA SSVCTrack at low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table
Published
August 11, 2026
Last Modified
September 25, 2026
Advisory Details (2)
Auto-updated Aug 11, 20262483133 – (CVE-2026-15561) CVE-2026-15561 undertow-core: OOM via missing limits in chunked trailer in EAP's Undertow
https://bugzilla.redhat.com/show_bug.cgi?id=2483133CVE-2026-15561 - Red Hat Customer Portal
Affected: Red Hat Enterprise Linux 8 or OpenShift Container Platform 4, is affected by this vulnerability and a fix may be released to a
https://access.redhat.com/security/cve/CVE-2026-15561Vendor Advisories for CVE-2026-15561(8)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
- RHSA-2026:70230Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.8 security update
- RHSA-2026:70228Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.8 security update
- RHSA-2026:70229Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 8.1.8 security update
- RHSA-2026:53806Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 7.4.25 security update
- RHSA-2026:53646Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 7.4.25 Security update
- RHSA-2026:53645Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 7.4.25 Security update
- RHSA-2026:53644Red Hat Product SecurityHigh
Red Hat Security Advisory: Red Hat JBoss Enterprise Application Platform 7.4.25 security pdate
- GHSA-fhmg-q5fc-2m8vGitHub Security AdvisoriesHigh
A flaw was found in EAP's undertow http/1.1 chunked-transfer decoder. missing limits on size and...
Patch Availability(7)
| Vendor / Ecosystem | Fix (by version range) / Patch | Released | Source |
|---|---|---|---|
| redhat | eap8-xml-security-0:3.0.6-1.redhat_00001.1.el9eap | 2026-09-22 | redhat |
| redhat | eap8-xml-security-0:3.0.6-1.redhat_00001.1.el10eap | 2026-09-22 | redhat |
| redhat | eap8-xml-security-0:3.0.6-1.redhat_00001.1.el8eap | 2026-09-22 | redhat |
| redhat | io.undertow/undertow-core:2.2.40.SP3-redhat-00001 | 2026-08-11 | redhat |
| redhat | eap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el9eap | 2026-08-11 | redhat |
| redhat | eap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el7eap | 2026-08-11 | redhat |
| redhat | eap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el8eap | 2026-08-11 | redhat |
Patches are aggregated from vendor advisories (Red Hat, Microsoft, Cisco, GitHub) and package ecosystems (OSV, GHSA). Multiple rows for the same upstream release have been deduplicated.
Affected Packages
(1 across 1 ecosystem)
Debian:14(1)
| Package | Vulnerable range | Fix by version range | Dependents |
|---|---|---|---|
| undertow | 1.3.11-1 ... 2.3.8-2 (56 versions) |
| — |
Weakness Classification(1)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 29× in last 7d / 163× in last 30d)
Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.
Showing the most recent 100 of 326 total refreshes for this CVE.
- 2026-10-04 23:21 UTCEPSS rescore
- 2026-10-04 22:47 UTCVendor advisory
- 2026-10-04 22:47 UTCGHSA enrichment
- 2026-10-04 09:17 UTCVendor advisory
- 2026-10-04 09:17 UTCGHSA enrichment
- 2026-10-03 21:35 UTCEG score recompute
- 2026-10-03 21:35 UTCVendor advisory
- 2026-10-03 21:35 UTCGHSA enrichment
- 2026-10-03 14:25 UTCEPSS rescore
- 2026-10-02 22:30 UTCEG score recompute
- 2026-10-02 22:30 UTCVendor advisory
- 2026-10-02 22:29 UTCGHSA enrichment
- 2026-10-02 09:14 UTCEG score recompute
- 2026-10-02 09:14 UTCVendor advisory
- 2026-10-02 09:14 UTCGHSA enrichment
- 2026-10-01 19:49 UTCEPSS rescore
- 2026-10-01 09:32 UTCVendor advisory
- 2026-10-01 09:32 UTCGHSA enrichment
- 2026-09-30 22:22 UTCEG score recompute
- 2026-09-30 22:22 UTCVendor advisory
- 2026-09-30 22:22 UTCGHSA enrichment
- 2026-09-30 15:02 UTCEPSS rescore
- 2026-09-29 15:20 UTCEPSS rescore
- 2026-09-29 05:18 UTCEG score recompute
- 2026-09-29 05:18 UTCVendor advisory
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- 2026-09-29 05:18 UTCGHSA enrichment
- 2026-09-28 13:51 UTCEPSS rescore
- 2026-09-28 13:13 UTCVendor advisory
- 2026-09-28 13:13 UTCGHSA enrichment
- 2026-09-28 02:21 UTCEG score recompute
- 2026-09-28 02:21 UTCVendor advisory
- 2026-09-28 02:21 UTCGHSA enrichment
- 2026-09-27 13:47 UTCEPSS rescore
- 2026-09-27 11:03 UTCEG score recompute
- 2026-09-27 11:03 UTCVendor advisory
- 2026-09-27 11:03 UTCGHSA enrichment
- 2026-09-26 15:58 UTCEPSS rescore
- 2026-09-25 13:24 UTCEG score recompute
- 2026-09-25 13:24 UTCVendor advisory
- 2026-09-25 13:24 UTCGHSA enrichment
- 2026-09-25 13:04 UTCEG score recompute
- 2026-09-25 13:04 UTCVendor advisory
- 2026-09-25 13:04 UTCGHSA enrichment
- 2026-09-25 03:57 UTCEG score recompute
- 2026-09-25 03:57 UTCVendor advisory
- 2026-09-25 03:57 UTCGHSA enrichment
- 2026-09-24 11:56 UTCVendor advisory
- 2026-09-24 11:56 UTCGHSA enrichment
- 2026-09-24 01:04 UTCVendor advisory
- 2026-09-24 01:04 UTCGHSA enrichment
- 2026-09-23 14:12 UTCEG score recompute
- 2026-09-23 14:12 UTCVendor advisory
- 2026-09-23 14:11 UTCGHSA enrichment
- 2026-09-23 03:19 UTCVendor advisory
- 2026-09-23 03:19 UTCGHSA enrichment
- 2026-09-22 16:27 UTCEG score recompute
- 2026-09-22 16:27 UTCVendor advisory
- 2026-09-22 16:27 UTCGHSA enrichment
- 2026-09-22 15:40 UTCEG score recompute
- 2026-09-22 15:40 UTCVendor advisory
- 2026-09-22 15:40 UTCGHSA enrichment
- 2026-09-22 10:07 UTCVendor advisory
- 2026-09-22 10:07 UTCGHSA enrichment
- 2026-09-21 21:56 UTCEG score recompute
- 2026-09-21 21:56 UTCVendor advisory
- 2026-09-21 21:56 UTCGHSA enrichment
- 2026-09-21 11:02 UTCVendor advisory
- 2026-09-21 11:02 UTCGHSA enrichment
- 2026-09-20 21:24 UTCEG score recompute
- 2026-09-20 21:24 UTCVendor advisory
- 2026-09-20 21:24 UTCGHSA enrichment
- 2026-09-20 10:26 UTCVendor advisory
- 2026-09-20 10:26 UTCGHSA enrichment
- 2026-09-19 23:20 UTCEG score recompute
- 2026-09-19 23:20 UTCVendor advisory
- 2026-09-19 23:20 UTCGHSA enrichment
- 2026-09-19 12:27 UTCVendor advisory
- 2026-09-19 12:27 UTCGHSA enrichment
- 2026-09-18 22:14 UTCEG score recompute
- 2026-09-18 22:14 UTCVendor advisory
- 2026-09-18 22:14 UTCGHSA enrichment
- 2026-09-18 19:27 UTCEPSS rescore
- 2026-09-18 11:22 UTCVendor advisory
- 2026-09-18 11:22 UTCGHSA enrichment
- 2026-09-18 00:28 UTCEG score recompute
- 2026-09-18 00:28 UTCVendor advisory
- 2026-09-18 00:28 UTCGHSA enrichment
- 2026-09-17 23:43 UTCEG score recompute
- 2026-09-17 23:43 UTCVendor advisory
- 2026-09-17 23:43 UTCGHSA enrichment
- 2026-09-17 19:28 UTCEG score recompute
- 2026-09-17 19:28 UTCVendor advisory
- 2026-09-17 19:28 UTCGHSA enrichment
- 2026-09-17 18:29 UTCEG score recompute
- 2026-09-17 18:29 UTCVendor advisory
- 2026-09-17 18:29 UTCGHSA enrichment
- 2026-09-17 14:03 UTCVendor advisory
- 2026-09-17 14:03 UTCGHSA enrichment
- 2026-09-17 00:39 UTCEG score recompute
- 2026-09-17 00:39 UTCVendor advisory
Related CVEs(same product + same vendor + same CWE)
Same product
10 shownDebian:14:undertow
Same vendor
10 shownredhat:RHSA-2026:53644
Frequently asked(5)
What is CVE-2026-15561?
When was CVE-2026-15561 disclosed?
Is CVE-2026-15561 actively exploited?
What is the CVSS score of CVE-2026-15561?
How do I remediate CVE-2026-15561?
Dependency Blast Radius
See which npm, PyPI, Go, and Maven packages are affected by CVE-2026-15561
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