CVE-2025-12543

CRITICALNVD 9.69.6
EchelonGraph scoreMEDIUM confidence

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

Score 9.6 from GitHub Security Advisory (severity: CRITICAL) published 2026-01-07. NVD baseline CVSS 9.6; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3
Trending — 4 sources updated this weekElevated

Also known asEUVD-2026-1207 (ENISA EUVD) · GHSA-j382-5jj3-vw4j (GitHub Security Advisories)Source: ENISA EUVD

9.6EG
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).
  • CISA's Vulnrichment rates exploitation as PoC; EchelonGraph holds no exploit-code reference for it
CISA-KEV: Not listedEPSS PROB: 1.3%CVSS: 9.6Exploit: No code on recordExposed services: Not assessed

A fix is available — apply it.

A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications. The Undertow library fails to properly validate the Host header in incoming HTTP requests.As a result, requests containing malformed or malicious Host headers are processed without rejection, enabling attackers to poison caches, perform internal network scans, or hijack user sessions.

CVSS v3
9.6
EG Score
9.6CRITICALmedium confidence
EG Risk
59
EG Risk 59/100

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)
Severity96% × 45%
Impact severity (EG Severity): CVSS 9.6 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation40% × 40%
EchelonGraph's fixed weight for EG-KEV Tier 3 (Elevated): a constant, not a probability.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at low, Track* at medium and Attend at high mission impact.
Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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
1.3%
EPSS %ILE
71st
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 (9.6): severity, escalated by confirmed exploitation. This CVE's 9.6 is its impact severity (EG Severity), not escalated.

EG Severity
9.6 CRITICALCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
1.3% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-01). 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, Track* at medium and Attend at high mission impact.CISA BOD 26-04: 14 days if the affected system is publicly exposed; Fix on system upgrade 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, Track* at medium and Attend at high mission impact.

A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.

Exploitation public PoC (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact total (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; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact total (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

January 7, 2026

Last Modified

October 14, 2026

Advisory Details (12)

Auto-updated Oct 7, 2026
Patch available. Sources: redhat.
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:4915
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:3892
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:3891
Red HatMentions a patch (unverified)
https://access.redhat.com/errata/RHSA-2026:3890
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:3889
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 7.

https://access.redhat.com/errata/RHSA-2026:33372
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 7. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:33371
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8.

https://access.redhat.com/errata/RHSA-2026:0386
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:0384
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:0383
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 9. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:4917
Red HatMentions a patch (unverified)

Affected: Red Hat Enterprise Linux 8. Red Hat Product Security has rated this update as having a security impact of Important. A Common

https://access.redhat.com/errata/RHSA-2026:4916

Patch Availability(20)

Vendor / EcosystemFix (by version range) / PatchReleasedSource
ubuntulibundertow-java-doc (2.2.16-1ubuntu0.1~esm1) @ jammy2026-11-01ubuntu
redhatrh-sso7-keycloak-0:18.0.20-1.redhat_00001.1.el7sso2026-10-06redhat
redhatrh-sso7-keycloak-0:18.0.20-1.redhat_00001.1.el8sso2026-10-06redhat
redhatrh-sso7-keycloak-0:18.0.20-1.redhat_00001.1.el9sso2026-10-06redhat
redhatrh-sso-7/sso76-openshift-rhel8:7.6-852026-10-05redhat
redhatundertow-core2026-10-05redhat
redhateap7-undertow-0:2.0.41-8.SP9_redhat_00001.1.el7eap2026-06-30redhat
redhateap7-undertow-0:1.4.18-21.SP19_redhat_00001.1.ep7.el72026-06-30redhat
redhateap7-wildfly-0:7.4.24-4.GA_redhat_00002.1.el9eap2026-03-18redhat
redhateap7-wildfly-0:7.4.24-4.GA_redhat_00002.1.el7eap2026-03-18redhat
redhatio.undertow/undertow-core:2.2.39.Final-redhat-000012026-03-18redhat
redhateap7-wildfly-0:7.4.24-4.GA_redhat_00002.1.el8eap2026-03-18redhat
redhateap8-undertow-0:2.3.23-1.SP3_redhat_00001.1.el9eap2026-03-05redhat
redhateap8-undertow-0:2.3.23-1.SP3_redhat_00001.1.el8eap2026-03-05redhat
redhatio.undertow/undertow-core:2.3.20.SP4-redhat-000012026-01-08redhat
redhateap8-wildfly-javadocs-0:8.1.1-4.GA_redhat_00007.1.el9eap2026-01-08redhat
redhateap8-wildfly-javadocs-0:8.1.1-4.GA_redhat_00007.1.el8eap2026-01-08redhat
mavenio.undertow:undertow-core—ghsa
mavenio.undertow:undertow-core @ 2.2.39.Final (fixes < 2.2.39.Final)—ghsa
mavenio.undertow:undertow-core @ 2.3.21.Final (fixes >= 2.3.0.Alpha1, < 2.3.21.Final)—ghsa

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

(2 across 2 ecosystems)
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
—
Maven(1)
PackageVulnerable rangeFix by version rangeDependents
io.undertow:undertow-core1.0.0.Alpha1 ... 2.2.9.Final (307 versions)
  • 2.3.0.Alpha1 up to 2.3.21.Final: fixed in 2.3.21.Final
  • every version up to 2.2.39.Final: fixed in 2.2.39.Final
—

Weakness Classification(1)

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

Additional Vendor Advisories

(1)

Vendors that published advisories for this CVE beyond the curated set above. Broader coverage but minimal per-row detail — click through for the original advisory.

Data Freshness Timeline

(refreshed 21× in last 7d / 86× 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 98 of 266 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. 2 repeat rows among the latest 100 are merged into the row they repeat. The 168 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-01 19:40 UTCEG score recompute
  2. 2026-11-01 19:40 UTCVendor advisory
  3. 2026-11-01 19:40 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  4. 2026-11-01 08:09 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  5. 2026-11-01 08:09 UTCEG score recompute
  6. 2026-10-31 18:32 UTCEG score recompute
  7. 2026-10-31 16:30 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  8. 2026-10-30 17:17 UTCEG score recompute
  9. 2026-10-30 17:17 UTCVendor advisory
  10. 2026-10-30 16:32 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  11. 2026-10-29 16:31 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  12. 2026-10-29 16:09 UTCEG score recompute
  13. 2026-10-29 16:09 UTCVendor advisory
  14. 2026-10-28 16:30 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  15. 2026-10-28 14:59 UTCEG score recompute
  16. 2026-10-28 14:59 UTCVendor advisory
  17. 2026-10-27 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  18. 2026-10-27 13:40 UTCEG score recompute
  19. 2026-10-27 13:40 UTCVendor advisory
  20. 2026-10-26 16:29 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  21. 2026-10-26 12:00 UTCVendor advisory
  22. 2026-10-25 16:47 UTCEG score recompute
  23. 2026-10-25 16:31 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  24. 2026-10-25 10:41 UTCEG score recompute
  25. 2026-10-25 10:41 UTCVendor advisory
Show 73 more
  1. 2026-10-24 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  2. 2026-10-24 09:33 UTCEG score recompute
  3. 2026-10-24 09:33 UTCVendor advisory
  4. 2026-10-23 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  5. 2026-10-23 08:24 UTCEG score recompute
  6. 2026-10-23 08:24 UTCVendor advisory
  7. 2026-10-22 16:32 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  8. 2026-10-22 07:14 UTCEG score recompute
  9. 2026-10-22 07:14 UTCVendor advisory
  10. 2026-10-21 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  11. 2026-10-21 06:06 UTCEG score recompute
  12. 2026-10-21 06:06 UTCVendor advisory
  13. 2026-10-20 16:31 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  14. 2026-10-20 04:57 UTCEG score recompute
  15. 2026-10-20 04:57 UTCVendor advisory
  16. 2026-10-19 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  17. 2026-10-19 03:46 UTCEG score recompute
  18. 2026-10-19 03:46 UTCVendor advisory
  19. 2026-10-18 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  20. 2026-10-18 05:51 UTCEG score recompute
  21. 2026-10-18 02:35 UTCEG score recompute
  22. 2026-10-18 02:35 UTCVendor advisory
  23. 2026-10-17 16:32 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  24. 2026-10-17 01:27 UTCEG score recompute
  25. 2026-10-17 01:27 UTCVendor advisory
  26. 2026-10-16 16:37 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  27. 2026-10-16 00:18 UTCEG score recompute
  28. 2026-10-16 00:18 UTCVendor advisory
  29. 2026-10-15 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  30. 2026-10-14 17:29 UTCVendor advisory
  31. 2026-10-14 16:46 UTCEG score recompute
  32. 2026-10-14 16:46 UTCVendor advisory
  33. 2026-10-14 16:31 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  34. 2026-10-14 14:49 UTCEG score recompute
  35. 2026-10-14 14:49 UTCVendor advisory
  36. 2026-10-13 16:31 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  37. 2026-10-13 13:37 UTCVendor advisory
  38. 2026-10-12 17:25 UTCEG score recompute
  39. 2026-10-12 16:32 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  40. 2026-10-12 12:26 UTCVendor advisory
  41. 2026-10-11 20:55 UTCEG score recompute
  42. 2026-10-11 19:05 UTCEG score recompute
  43. 2026-10-11 15:46 UTCEG score recompute
  44. 2026-10-11 13:46 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  45. 2026-10-10 19:58 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  46. 2026-10-09 20:06 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  47. 2026-10-08 17:08 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  48. 2026-10-07 23:46 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  49. 2026-10-06 17:20 UTCVendor advisory
  50. 2026-10-06 17:13 UTCVendor advisory
  51. 2026-10-06 16:52 UTCEG score recompute
  52. 2026-10-06 16:52 UTCVendor advisory
  53. 2026-10-06 15:16 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  54. 2026-10-06 12:28 UTCVendor advisory
  55. 2026-10-06 11:50 UTCVendor advisory
  56. 2026-10-06 00:26 UTCVendor advisory
  57. 2026-10-05 23:38 UTCEG score recompute
  58. 2026-10-05 23:38 UTCVendor advisory
  59. 2026-10-05 17:42 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  60. 2026-10-04 23:21 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  61. 2026-10-03 14:24 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  62. 2026-10-01 19:48 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  63. 2026-09-30 15:02 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  64. 2026-09-28 13:50 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  65. 2026-09-27 04:45 UTCOSV refresh
  66. 2026-09-26 15:57 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  67. 2026-09-24 14:02 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  68. 2026-09-23 13:46 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  69. 2026-09-22 14:47 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  70. 2026-09-20 20:14 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  71. 2026-09-18 19:27 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  72. 2026-09-16 14:06 UTCEPSS rescoreEPSS 1.4% · 70th percentile
  73. 2026-09-16 05:13 UTCEPSS rescoreEPSS 1.4% · 70th percentile

Frequently asked(5)

What is CVE-2025-12543?
CVE-2025-12543 is a critical-severity vulnerability; its CVE record was published on January 7, 2026. A flaw was found in the Undertow HTTP server core, which is used in WildFly, JBoss EAP, and other Java applications. The Undertow library fails to properly validate the Host header in incoming HTTP requests.As a result, requests containing malformed or malicious Host headers are processed without…
When was CVE-2025-12543 made public?
CVE-2025-12543 was made public on January 8, 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 January 7, 2026. EchelonGraph's copy of the record carries a last-modified date of October 14, 2026; the record at its source may have been updated since.
Is CVE-2025-12543 actively exploited?
CVE-2025-12543 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1.3% probability of exploitation in the next 30 days (71st percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2025-12543?
CVE-2025-12543 has a CVSS v3 base score of 9.6 (NVD).
How do I remediate CVE-2025-12543?
A fix for CVE-2025-12543 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2025-12543 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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