CVE-2026-15561

HIGHPre-NVD 7.57.5
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to the CVSS score beside it.

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.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, a secondary CVSS source
Trending — 4 sources updated this week

Also known asEUVD-2026-55985 (ENISA EUVD) · GHSA-fhmg-q5fc-2m8v (GitHub Security Advisories)Source: ENISA EUVD

7.5EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines at low or medium mission impact and sooner than that at high (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.7%CVSS: 7.5Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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.

CVSS v3
7.5
EG Score
7.5HIGHmedium confidence
EG Risk
49
EG Risk 49/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity75% × 45%
Impact severity (EG Severity): CVSS 7.5 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.9% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability100% × 15%
CISA's SSVC Automatable value: yes (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).
Exploitation none (CISA Vulnrichment) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
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
0.7%
EPSS %ILE
53rd
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.5): severity, escalated by confirmed exploitation. This CVE's 7.5 is its impact severity (EG Severity), not escalated.

EG Severity
7.5 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.7% within 30 daysSource: FIRST EPSS. FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)14 days if the affected system is publicly exposed; 60 days if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

August 11, 2026

Last Modified

November 1, 2026

Advisory Details (2)

Auto-updated Aug 11, 2026
Patch available. Sources: redhat.
Red Hat

2483133 – (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=2483133
Red HatMentions a patch (unverified)

CVE-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-2026-15561

Patch Availability(8)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
redhatio.undertow/undertow-core:2.3.26.SP3-redhat-000012026-09-22redhat
redhateap8-xml-security-0:3.0.6-1.redhat_00001.1.el9eap2026-09-22redhat
redhateap8-xml-security-0:3.0.6-1.redhat_00001.1.el8eap2026-09-22redhat
redhateap8-xml-security-0:3.0.6-1.redhat_00001.1.el10eap2026-09-22redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el9eap2026-08-11redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el7eap2026-08-11redhat
redhateap7-wildfly-0:7.4.25-2.GA_redhat_00001.1.el8eap2026-08-11redhat
redhatundertow-core2026-08-11redhat

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)
PackageVulnerable rangeFix by version rangeDependents
undertow1.3.11-1 ... 2.3.8-2 (56 versions)
  • every version on: no fix on record
—

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 16× in last 7d / 87× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. 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. An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). Most recent first.

Showing the most recent 100 of 404 refreshes on record for this CVE.

A repeat, a row identical to one the same pipeline wrote less than 10 seconds earlier, is not a separate refresh and is not counted. None are among the latest 100 rows. The 304 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.7% · 53rd percentile
  2. 2026-11-01 01:27 UTCEG score recompute
  3. 2026-11-01 01:27 UTCVendor advisory
  4. 2026-11-01 01:27 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  5. 2026-11-01 00:34 UTCEG score recompute
  6. 2026-11-01 00:34 UTCVendor advisory
  7. 2026-11-01 00:33 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  8. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.8% · 58th percentile
  9. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.8% · 58th percentile
  10. 2026-10-30 12:55 UTCEG score recompute
  11. 2026-10-30 12:55 UTCVendor advisory
  12. 2026-10-30 12:55 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  13. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.8% · 58th percentile
  14. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  15. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  16. 2026-10-26 16:30 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  17. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.8% · 57th percentile
  18. 2026-10-25 14:47 UTCEG score recompute
  19. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.5% · 39th percentile
  20. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  21. 2026-10-22 23:28 UTCEG score recompute
  22. 2026-10-22 23:28 UTCVendor advisory
  23. 2026-10-22 23:28 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  24. 2026-10-22 22:21 UTCEG score recompute
  25. 2026-10-22 22:21 UTCVendor advisory
Show 75 more
  1. 2026-10-22 22:21 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  2. 2026-10-22 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  3. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  4. 2026-10-20 20:26 UTCEG score recompute
  5. 2026-10-20 20:26 UTCVendor advisory
  6. 2026-10-20 20:26 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  7. 2026-10-20 19:28 UTCEG score recompute
  8. 2026-10-20 19:28 UTCVendor advisory
  9. 2026-10-20 19:28 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  10. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  11. 2026-10-20 15:27 UTCEG score recompute
  12. 2026-10-20 15:27 UTCVendor advisory
  13. 2026-10-20 15:26 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  14. 2026-10-20 14:22 UTCEG score recompute
  15. 2026-10-20 14:22 UTCVendor advisory
  16. 2026-10-20 14:22 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  17. 2026-10-19 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  18. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  19. 2026-10-18 05:01 UTCEG score recompute
  20. 2026-10-17 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  21. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  22. 2026-10-16 11:28 UTCEG score recompute
  23. 2026-10-16 11:28 UTCVendor advisory
  24. 2026-10-16 11:28 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  25. 2026-10-15 17:27 UTCEG score recompute
  26. 2026-10-15 17:27 UTCVendor advisory
  27. 2026-10-15 17:27 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  28. 2026-10-15 16:39 UTCEG score recompute
  29. 2026-10-15 16:39 UTCVendor advisory
  30. 2026-10-15 16:39 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  31. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  32. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  33. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  34. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  35. 2026-10-12 16:31 UTCEG score recompute
  36. 2026-10-11 20:10 UTCEG score recompute
  37. 2026-10-11 17:22 UTCEG score recompute
  38. 2026-10-11 14:55 UTCEG score recompute
  39. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  40. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  41. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.5% · 38th percentile
  42. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  43. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  44. 2026-10-07 05:32 UTCVendor advisory
  45. 2026-10-07 05:32 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  46. 2026-10-06 18:06 UTCEG score recompute
  47. 2026-10-06 18:06 UTCVendor advisory
  48. 2026-10-06 18:06 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  49. 2026-10-06 15:17 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  50. 2026-10-05 18:20 UTCEG score recompute
  51. 2026-10-05 18:20 UTCVendor advisory
  52. 2026-10-05 18:20 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  53. 2026-10-05 17:42 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  54. 2026-10-04 23:21 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  55. 2026-10-04 22:47 UTCVendor advisory
  56. 2026-10-04 22:47 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  57. 2026-10-04 09:17 UTCVendor advisory
  58. 2026-10-04 09:17 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  59. 2026-10-03 21:35 UTCEG score recompute
  60. 2026-10-03 21:35 UTCVendor advisory
  61. 2026-10-03 21:35 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  62. 2026-10-03 14:25 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  63. 2026-10-02 22:30 UTCEG score recompute
  64. 2026-10-02 22:30 UTCVendor advisory
  65. 2026-10-02 22:29 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  66. 2026-10-02 09:14 UTCEG score recompute
  67. 2026-10-02 09:14 UTCVendor advisory
  68. 2026-10-02 09:14 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  69. 2026-10-01 19:49 UTCEPSS rescoreEPSS 0.5% · 37th percentile
  70. 2026-10-01 09:32 UTCVendor advisory
  71. 2026-10-01 09:32 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  72. 2026-09-30 22:22 UTCEG score recompute
  73. 2026-09-30 22:22 UTCVendor advisory
  74. 2026-09-30 22:22 UTCGHSA enrichmentGHSA-fhmg-q5fc-2m8v · GitHub severity HIGH · GitHub CVSS 7.5
  75. 2026-09-30 15:02 UTCEPSS rescoreEPSS 0.5% · 37th percentile

Frequently asked(5)

What is CVE-2026-15561?
CVE-2026-15561 is a high-severity vulnerability; its CVE record was published on August 11, 2026. 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.
When was CVE-2026-15561 made public?
CVE-2026-15561 was made public on August 11, 2026: that is the date its CVE record's CNA, Red Hat, Inc., gives for when the vulnerability was made public. The CVE record itself was published on August 11, 2026. EchelonGraph's copy of the record carries a last-modified date of November 1, 2026; the record at its source may have been updated since.
Is CVE-2026-15561 actively exploited?
CVE-2026-15561 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.7% probability of exploitation in the next 30 days (53rd percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-15561?
CVE-2026-15561 has a CVSS base score of 7.5 (a secondary CVSS source that NVD displays; NVD's own analysis pending).
How do I remediate CVE-2026-15561?
A fix for CVE-2026-15561 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-15561 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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