CVE-2026-9704

highpriority · track · 35EPSS 0.003 · 25 %ileDEEUUS

grimoire priorityP2 · Scheduled

Exploitable?

—

no known exploitation

Likely / severe?

0.32% (25th) EPSS

CVSS 8.8 · high

Is it mine?

13 products

Check your exposure

Who says so?

5 sources

cnnvd · enisa_euvd · cert_bund · nvd

EPSS · scored 2026-10-27

A flaw was found in Keycloak. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subject_token JSON Web Token (JWT) to the TokenEndpoint. When the token exceeds a 4000-character limit, it is silently dropped, causing the system to fall back to client credentials. This allows the user to gain the permissions of the client's service account, leading to privilege escalation.

cvss

Technical severity, 0–10. One row per scoring source.

8.8

010

base score 0–10 · higher = more severe · hover a vector to decode⚠ sources disagree · medium–high · 6.8–8.8

v3.18.8highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:Hprimary · NVD / NIST USexploitability 2.8 · impact 5.9

v3.16.8mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Nsecondary · ENISA EU

v3.16.8mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Nsecondary · secalert@redhat.com USexploitability 1.6 · impact 5.2

v3.16.8mediumCVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:Nsecondary · OSV

v3.18.1highCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H/E:Usecondary · CVSS-BT (t0sche)

ssvc

A stakeholder decision — act, attend, or track — from exploitation and impact.

Exploitation: none · Automatable: no · Technical Impact: totalcoordinatorcisa_ssvcUS

weaknesses

The CWE weakness classes this flaw belongs to.

CWE-1284USCWE-1284US

affected products (13)

Products and version ranges known to be affected.

Open Source Keycloakall versionscert_bundDEcpe:/a:keycloak:keycloak:-
Open Source Keycloak <26.6.3all versionscert_bundDE
Open Source Keycloak <26.7.0all versionscert_bundDE
Red Hat Enterprise Linuxall versionscert_bundDEcpe:/o:redhat:enterprise_linux:-
Open Source Keycloak< 26.6.3cert_bundDE
Open Source Keycloak< 26.7.0cert_bundDE
Red Hat Red Hat build of Keycloak 26.4< 26.4-19enisa_euvdEU
Red Hat Red Hat build of Keycloak 26.4< 26.4.13-1enisa_euvdEU
Red Hat Red Hat build of Keycloak 26.6< 26.6-6enisa_euvdEU
Red Hat Red Hat build of Keycloak 26.6< 26.6.3-3enisa_euvdEU
redhat build of keycloakall versionsnvdUScpe:2.3:a:redhat:build_of_keycloak:*:*:*:*:*:*:*:*
Maven org.keycloak:keycloak-server-spi-private< 26.6.3osvUSpkg:maven/org.keycloak/keycloak-server-spi-private
Maven org.keycloak:keycloak-services< 26.6.3osvUSpkg:maven/org.keycloak/keycloak-services

advisories (2)

Vendor and ecosystem advisories describing this.

WID-SEC-W-2026-1708Keycloak: Mehrere SchwachstellenDeutsch2026-05-27csaf · cert_bundDE
Ein Angreifer kann mehrere Schwachstellen in Keycloak ausnutzen, um seine Privilegien zu erhöhen, um Informationen offenzulegen, um Sicherheitsvorkehrungen zu umgehen und um einen Denial of Service Angriff durchzuführen.
GHSA-rr5q-3xwr-f323Keycloak Vulnerable to Improper Validation of Specified Quantity in Input2026-05-27ghsa · osvUS
A flaw was found in Keycloak. An authenticated user with low privileges can exploit this vulnerability by sending an oversized subject_token JSON Web Token (JWT) to the TokenEndpoint. When the token exceeds a 4000-character limit, it is silently dropped, causing the system to fall back to client credentials. This allows the user to gain the permissions of the client's service account, leading to privilege escalation.

also known as (3)

Other names and identifiers for this entity.

sources

Which sources assert this record, and when.

cnnvd enisa_euvd cert_bund nvd osv NVD CVE.org MITRE

published 2026-05-27modified 2026-06-26

references (15)

External citations — patches, advisories, analysis.

scry

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