CVE-2026-18212
Keycloak-services: keycloak-services: saml redirect deflate helpers leak native zlib state
No known exploitation. EPSS puts it in the 42nd percentile. Only a workaround so far.
What to do
No fixed build is published yet. The vendor describes a workaround.
What it is
From the CVE record
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.
In plain language
No plain-language summary for this CVE yet.
Exploitation
Where each signal puts this CVE on the scale from published to confirmed exploited.
- CISA KEV
Not in the catalog. CISA has not confirmed exploitation.
- Public exploits
No public exploit or proof of concept found in the sources we track.
- EPSS
0.5% chance of exploitation activity in the next 30 days, which ranks it in the 42nd percentile of scored CVEs.
Exploit Prediction Scoring System, FIRST.org. A probability, not a confirmation.
Lifecycle
6 events over 0 days, from the signal feeds we watch.
- Workaround availableworkaround available, published, weakness classified, record updated, record updated
Affected products
- Red Hat build of Keycloak 26.4Web & CMS Plugins
- Red Hat build of Keycloak 26.4.16Operating Systems / linux-distro
- Red Hat build of Keycloak 26.6Security Products / identity-access-mgmt
- Red Hat build of Keycloak 26.6.7Operating Systems / linux-distro
- Red Hat Data Grid 8Databases / cache-message-queue
- Red Hat JBoss Enterprise Application Platform Expansion PackOperating Systems / linux-distro
- Red Hat Single Sign-On 7Security Products / identity-access-mgmt
Technical detail
CVSS 3.1 vector
Open in the CVSS calculatorCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Scored 7.5 by NVD.
How it is reached
- Attack Vector NetworkExploitable remotely over the network without any special conditions
- Attack Complexity LowNo special conditions — the attack can be reliably reproduced
- Privileges Required NoneNo authentication required — anyone can exploit this
- User Interaction NoneNo user interaction needed — fully automated exploitation
Scope
- Scope UnchangedImpact is limited to the vulnerable component itself
Impact if exploited
- Confidentiality NoneNo confidentiality impact
- Integrity NoneNo integrity impact
- Availability HighTotal denial of service — the component is completely unavailable
Weaknesses
Sources
References in the record
- access.redhat.com/errata/RHSA-2026:68276
- access.redhat.com/errata/RHSA-2026:68277
- access.redhat.com/errata/RHSA-2026:68278
And 3 more references. See all after sign-in
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