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
Elevated

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 2026-11-12). 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

November 4, 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 (1.3.16-1ubuntu0.1~esm1) @ xenial2026-11-12ubuntu
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 @ 2.3.21.Final (fixes >= 2.3.0.Alpha1, < 2.3.21.Final)—ghsa
mavenio.undertow:undertow-core @ 2.2.39.Final (fixes < 2.2.39.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 / 73× 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 its CVE.org record (CNA or CISA ADP). 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). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

Showing the most recent 100 of 317 rows 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 217 oldest rows on record are not shown and were not checked, so the counts can still include repeats.

  1. 2026-11-13 16:49 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  2. 2026-11-13 07:36 UTCEchelonGraph re-scored
  3. 2026-11-13 07:36 UTCVendor advisory
  4. 2026-11-13 07:36 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  5. 2026-11-12 16:32 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  6. 2026-11-12 06:28 UTCEchelonGraph re-scored
  7. 2026-11-12 06:28 UTCVendor advisory
  8. 2026-11-12 06:28 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  9. 2026-11-11 16:35 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  10. 2026-11-11 05:20 UTCEchelonGraph re-scored
  11. 2026-11-11 05:20 UTCVendor advisory
  12. 2026-11-11 05:20 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  13. 2026-11-10 16:39 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  14. 2026-11-10 04:12 UTCEchelonGraph re-scored
  15. 2026-11-10 04:12 UTCVendor advisory
  16. 2026-11-10 04:11 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  17. 2026-11-09 16:32 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  18. 2026-11-09 02:59 UTCEchelonGraph re-scored
  19. 2026-11-09 02:59 UTCVendor advisory
  20. 2026-11-09 02:59 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  21. 2026-11-08 16:36 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  22. 2026-11-08 01:51 UTCEchelonGraph re-scored
  23. 2026-11-08 01:51 UTCVendor advisory
  24. 2026-11-08 01:51 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  25. 2026-11-07 16:36 UTCEPSS rescoreEPSS 1.3% · 71st percentile
Show 75 more
  1. 2026-11-07 00:43 UTCEchelonGraph re-scored
  2. 2026-11-07 00:43 UTCVendor advisory
  3. 2026-11-07 00:43 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  4. 2026-11-06 16:33 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  5. 2026-11-05 23:35 UTCEchelonGraph re-scored
  6. 2026-11-05 23:35 UTCVendor advisory
  7. 2026-11-05 23:35 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  8. 2026-11-05 16:35 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  9. 2026-11-05 07:55 UTCOSV refresh
  10. 2026-11-04 22:27 UTCVendor advisory
  11. 2026-11-04 22:27 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  12. 2026-11-04 21:26 UTCEchelonGraph re-scored
  13. 2026-11-04 21:26 UTCVendor advisory
  14. 2026-11-04 21:26 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  15. 2026-11-04 16:32 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  16. 2026-11-03 22:27 UTCVendor advisory
  17. 2026-11-03 22:27 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  18. 2026-11-03 21:56 UTCEchelonGraph re-scored
  19. 2026-11-03 21:56 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  20. 2026-11-03 16:44 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  21. 2026-11-02 20:49 UTCEchelonGraph re-scored
  22. 2026-11-02 20:49 UTCVendor advisory
  23. 2026-11-02 20:49 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  24. 2026-11-02 16:42 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  25. 2026-11-01 19:40 UTCEchelonGraph re-scored
  26. 2026-11-01 19:40 UTCVendor advisory
  27. 2026-11-01 19:40 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  28. 2026-11-01 08:09 UTCGHSA enrichmentGHSA-j382-5jj3-vw4j · GitHub severity CRITICAL · GitHub CVSS 9.6
  29. 2026-11-01 08:09 UTCEchelonGraph re-scored
  30. 2026-10-31 18:32 UTCEchelonGraph re-scored
  31. 2026-10-31 16:30 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  32. 2026-10-30 17:17 UTCEchelonGraph re-scored
  33. 2026-10-30 17:17 UTCVendor advisory
  34. 2026-10-30 16:32 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  35. 2026-10-29 16:31 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  36. 2026-10-29 16:09 UTCEchelonGraph re-scored
  37. 2026-10-29 16:09 UTCVendor advisory
  38. 2026-10-28 16:30 UTCEPSS rescoreEPSS 1.3% · 71st percentile
  39. 2026-10-28 14:59 UTCEchelonGraph re-scored
  40. 2026-10-28 14:59 UTCVendor advisory
  41. 2026-10-27 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  42. 2026-10-27 13:40 UTCEchelonGraph re-scored
  43. 2026-10-27 13:40 UTCVendor advisory
  44. 2026-10-26 16:29 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  45. 2026-10-26 12:00 UTCVendor advisory
  46. 2026-10-25 16:47 UTCEchelonGraph re-scored
  47. 2026-10-25 16:31 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  48. 2026-10-25 10:41 UTCEchelonGraph re-scored
  49. 2026-10-25 10:41 UTCVendor advisory
  50. 2026-10-24 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  51. 2026-10-24 09:33 UTCEchelonGraph re-scored
  52. 2026-10-24 09:33 UTCVendor advisory
  53. 2026-10-23 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  54. 2026-10-23 08:24 UTCEchelonGraph re-scored
  55. 2026-10-23 08:24 UTCVendor advisory
  56. 2026-10-22 16:32 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  57. 2026-10-22 07:14 UTCEchelonGraph re-scored
  58. 2026-10-22 07:14 UTCVendor advisory
  59. 2026-10-21 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  60. 2026-10-21 06:06 UTCEchelonGraph re-scored
  61. 2026-10-21 06:06 UTCVendor advisory
  62. 2026-10-20 16:31 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  63. 2026-10-20 04:57 UTCEchelonGraph re-scored
  64. 2026-10-20 04:57 UTCVendor advisory
  65. 2026-10-19 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  66. 2026-10-19 03:46 UTCEchelonGraph re-scored
  67. 2026-10-19 03:46 UTCVendor advisory
  68. 2026-10-18 16:30 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  69. 2026-10-18 05:51 UTCEchelonGraph re-scored
  70. 2026-10-18 02:35 UTCEchelonGraph re-scored
  71. 2026-10-18 02:35 UTCVendor advisory
  72. 2026-10-17 16:32 UTCEPSS rescoreEPSS 1.3% · 70th percentile
  73. 2026-10-17 01:27 UTCEchelonGraph re-scored
  74. 2026-10-17 01:27 UTCVendor advisory
  75. 2026-10-16 16:37 UTCEPSS rescoreEPSS 1.3% · 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 November 4, 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

See which npm, PyPI, Go, and Maven packages are affected by CVE-2025-12543

Explore →

Is Your Infrastructure Affected by CVE-2025-12543?

EchelonGraph automatically scans your cloud infrastructure and maps CVE exposure using blast radius analysis.