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CVE-2026-18212 (GCVE-0-2026-18212)

Vulnerability from cvelistv5 – Published: 2026-09-16 14:54 – Updated: 2026-09-16 18:35
VLAI
Title
Keycloak-services: keycloak-services: saml redirect deflate helpers leak native zlib state
Summary
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.
Severity
7.5 (High)
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
SSVC
Exploitation: none Automatable: yes Technical Impact: partial
CISA Coordinator · CISA-ADP (v2.0.3)
Decision recorded 2026-09-16 18:25 UTC
CWE
  • CWE-401 - Missing Release of Memory after Effective Lifetime
Assigner
References
URL Tags
https://access.redhat.com/errata/RHSA-2026:68276 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:68277 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:68278 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/errata/RHSA-2026:68280 vendor-advisoryx_refsource_REDHAT
https://access.redhat.com/security/cve/CVE-2026-18212 vdb-entryx_refsource_REDHAT
https://bugzilla.redhat.com/show_bug.cgi?id=2508307 issue-trackingx_refsource_REDHAT
Impacted products
Vendor Product Version CPE status
Red Hat Red Hat build of Keycloak 26.4 Unaffected: 26.4.16-2 , < * (rpm)
    cpe:/a:redhat:build_keycloak:26.4::el9
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Red Hat Red Hat build of Keycloak 26.4 Unaffected: 26.4-26 , < * (rpm)
    cpe:/a:redhat:build_keycloak:26.4::el9
Create a notification for this product.
Red Hat Red Hat build of Keycloak 26.4.16     cpe:/a:redhat:build_keycloak:26.4::el9
Create a notification for this product.
Red Hat Red Hat build of Keycloak 26.6 Unaffected: 26.6.7-3 , < * (rpm)
    cpe:/a:redhat:build_keycloak:26.6::el9
Create a notification for this product.
Red Hat Red Hat build of Keycloak 26.6 Unaffected: 26.6-20 , < * (rpm)
    cpe:/a:redhat:build_keycloak:26.6::el9
Create a notification for this product.
Red Hat Red Hat build of Keycloak 26.6.7     cpe:/a:redhat:build_keycloak:26.6::el9
Create a notification for this product.
Red Hat Red Hat Data Grid 8     cpe:/a:redhat:jboss_data_grid:8
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Red Hat Red Hat JBoss Enterprise Application Platform Expansion Pack     cpe:/a:redhat:jbosseapxp
Create a notification for this product.
Red Hat Red Hat Single Sign-On 7     cpe:/a:redhat:red_hat_single_sign_on:7
Create a notification for this product.
Date Public
2026-09-16 12:57
Credits
Red Hat would like to thank Paul Bottinelli (Trail of Bits in collaboration with OpenAI) for reporting this issue.
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}



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Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.


Related by attack behaviour

Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.