CVE-2026-18212
Published: September 16th, 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 this by sending repeated malformed SAML requests, leading to native memory exhaustion and a denial of service.
HIGH
CVSS v3: 7.5
CVSS v3: 7.5
Status
| DocFilters Release | Package | State | Justification | Comment |
|---|---|---|---|---|
| daily | zlib (1.3) | Needs Triage | ||
| 26.3 | zlib (1.3) | Needs Triage | ||
| 26.2 | zlib (1.3) | Needs Triage | ||
| 26.1 | zlib (1.3) | Needs Triage | ||
| 25.4 | zlib (1.3) | Needs Triage | ||
| 25.3 | zlib (1.3) | Needs Triage | ||
| 25.2 | zlib (1.3) | Needs Triage | ||
| 25.1 | zlib (1.3) | Needs Triage | ||
| 24.4 | zlib (1.3) | Needs Triage | ||
| 24.4.0 | zlib (1.3) | Needs Triage | ||
| 24.3 | zlib (1.3) | Needs Triage | ||
| 24.2 | zlib (1.3) | Needs Triage | ||
| 24.1 | zlib (1.3) | Needs Triage | ||
| 23.3 | zlib (1.3) | Needs Triage | ||
| 23.2 | zlib (1.2.12) | Needs Triage | ||
| 23.1 | zlib (1.2.12) | Needs Triage | ||
| 22.4 | zlib (1.2.12) | Needs Triage | ||
| 22.3 | zlib (1.2.12) | Needs Triage | ||
| 22.2 | zlib (1.2.12) | Needs Triage | ||
| 22.1 | zlib (1.2.11) | Needs Triage | ||
| 21.11 | zlib (1.2.11) | Needs Triage | ||
| 21.8 | zlib (1.2.11) | Needs Triage | ||
| 21.5.0 | zlib (1.2.11) | Needs Triage | ||
| 21.2.0 | zlib (1.2.11) | Needs Triage | ||
| 11.4.19.3667 | zlib (1.2.11) | Needs Triage | ||
| 11.4.18.3599 | zlib (1.2.11) | Needs Triage | ||
| 11.4.16.3445 | zlib (1.2.11) | Needs Triage | ||
| 11.4.15.3368 | zlib (1.2.11) | Needs Triage | ||
| 11.4.14.3263 | zlib (1.2.11) | Needs Triage | ||
| 11.4.13.3179 | zlib (1.2.11) | Needs Triage | ||
| 11.4.12.3054 | zlib (1.2.11) | Needs Triage | ||
| 11.4.11.3040 | zlib (1.2.11) | Needs Triage | ||
| 11.4.11.2990 | zlib (1.2.11) | Needs Triage | ||
| 11.4.10.2934 | zlib (1.2.11) | Needs Triage | ||
| 11.4.9.2878 | zlib (1.2.11) | Needs Triage | ||
| 11.4.8.2822 | zlib (1.2.11) | Needs Triage |
Severity score breakdown
Attack Complexity
LOW
Attack Vector
NETWORK
Availability Impact
HIGH
Base Score
7.5
Base Severity
HIGH
Confidentiality Impact
NONE
Integrity Impact
NONE
Privileges Required
NONE
Scope
UNCHANGED
User Interaction
NONE
Vector String
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
Version
3.1