CVE-2026-18212

HIGHPre-NVD 7.57.5—
EchelonGraph scoreHIGH confidence

Score 7.5 from GitHub Security Advisory (severity: HIGH) published 2026-09-16. a secondary CVSS source baseline 7.5; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: epss, ghsa, secondary
Trending — Patch released this week
7.5EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 1%CVSS: 7.5Exploit: None knownExposed: 0

A fix is available — apply it.

A flaw was found in the SAML Redirect Binding implementation of Keycloak, an open-source identity and access management solution. The issue occurs because the custom DEFLATE compression and decompression helpers fail to release native zlib memory after use. An unauthenticated attacker can exploit this by sending repeated malformed SAML requests, leading to native memory exhaustion and a denial of service.

CVSS v3
7.5
EG Score
7.5(high)
EG Risk
49(Track)
EG Risk 49/100SSVC: Track

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 computed
Severity75% × 45%
Exploitation1% × 40%
Automatability100% × 15%
Action: Routine — remediate on your standard cadence.
EPSS PROB
1%
EPSS %ILE
43%
KEV
Not listed

Published

September 16, 2026

Last Modified

September 16, 2026

Advisory Details (6)

Auto-updated Sep 16, 2026
Patch available. Sources: redhat.
redhat

2508307 – (CVE-2026-18212) CVE-2026-18212 keycloak-services: keycloak-services: SAML Redirect DEFLATE helpers leak native zlib state

https://bugzilla.redhat.com/show_bug.cgi?id=2508307
redhat Patch Available

CVE-2026-18212 - 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-2026-18212
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:68280
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:68278
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:68277
redhat Patch Available
https://access.redhat.com/errata/RHSA-2026:68276

Vendor Advisories for CVE-2026-18212(3)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Patch Availability(3)

Vendor / EcosystemFixed in / PatchReleasedSource
redhatrhbk-openshift-rhel9/rhbk-openshift-rhel92026-09-16redhat
redhatrhbk/keycloak-rhel9-operator:26.6-202026-09-16redhat
redhatrhbk/keycloak-rhel9-operator:26.4-262026-09-16redhat

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.

Weakness Classification(1)

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

Additional Vendor Advisories

(2)

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 26× in last 7d / 26× 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.

  1. 2026-09-19 04:38 UTCEG score recompute
  2. 2026-09-19 04:38 UTCVendor advisory
  3. 2026-09-19 04:38 UTCGHSA enrichment
  4. 2026-09-18 19:27 UTCEPSS rescore
  5. 2026-09-18 17:16 UTCVendor advisory
  6. 2026-09-18 17:16 UTCGHSA enrichment
  7. 2026-09-18 05:53 UTCEG score recompute
  8. 2026-09-18 05:53 UTCVendor advisory
  9. 2026-09-18 05:53 UTCGHSA enrichment
  10. 2026-09-17 18:30 UTCVendor advisory
  11. 2026-09-17 18:30 UTCGHSA enrichment
  12. 2026-09-17 07:07 UTCGHSA enrichment
  13. 2026-09-16 19:45 UTCGHSA enrichment
  14. 2026-09-16 19:25 UTCEG score recompute
  15. 2026-09-16 19:25 UTCGHSA enrichment
  16. 2026-09-16 18:41 UTCEG score recompute
  17. 2026-09-16 18:41 UTCGHSA enrichment
  18. 2026-09-16 18:25 UTCEG score recompute
  19. 2026-09-16 18:25 UTCGHSA enrichment
  20. 2026-09-16 16:32 UTCEG score recompute
  21. 2026-09-16 16:32 UTCGHSA enrichment
  22. 2026-09-16 15:50 UTCEG score recompute
  23. 2026-09-16 15:50 UTCGHSA enrichment
  24. 2026-09-16 15:20 UTCEG score recompute
  25. 2026-09-16 15:01 UTCEG score recompute
Show 1 more
  1. 2026-09-16 15:00 UTCMITRE cvelistV5first tracked

Frequently asked(5)

What is CVE-2026-18212?
CVE-2026-18212 is a high vulnerability published on September 16, 2026. A flaw was found in the SAML Redirect Binding implementation of Keycloak, an open-source identity and access management solution. The issue occurs because the custom DEFLATE compression and decompression helpers fail to release native zlib memory after use. An unauthenticated attacker can exploit…
When was CVE-2026-18212 disclosed?
CVE-2026-18212 was first published in the National Vulnerability Database on September 16, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
Is CVE-2026-18212 actively exploited?
CVE-2026-18212 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 1% probability of exploitation in the next 30 days, which ranks it in the top 56.7% of all scored CVEs.
What is the CVSS score of CVE-2026-18212?
CVE-2026-18212 has a CVSS v3 base score of 7.5 (NVD).
How do I remediate CVE-2026-18212?
Patch to the fixed version published by the affected vendor. Where vendor advisories exist for CVE-2026-18212, EchelonGraph cross-links them in the Vendor Advisories panel below — those typically contain the canonical remediation steps, fixed version numbers, and any vendor-specific mitigations.

Dependency Blast Radius

Explore the affected products and dependency analysis for CVE-2026-18212

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