CVE-2021-26296 is a high-severity (CVSS 7.5) Cross-Site Request Forgery (CSRF) vulnerability in org.apache.myfaces.core:myfaces-core-module. 1 public exploit reference exists, so weaponization risk is real. A fix is available for org.apache.myfaces.core:myfaces-core-module — see the affected versions and patch details below.
Cryptographically weak CSRF tokens in Apache MyFaces
EPSS Exploitation Probability
Probability of exploitation in the next 30 days, from FIRST.org EPSS.
How urgent is this, really
CVE-2021-26296 by exploitation likelihood (EPSS) against impact (CVSS). Outside the shaded patch-first corner.
Where this sits among everything scored
Of 385,987 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Counts from FIRST.org, log-scaled.
Real-World Exposure
org.apache.myfaces.core:myfaces-core-module☕org.apache.myfaces.core:myfaces-core-module☕org.apache.myfaces.core:myfaces-core-module☕org.apache.myfaces.core:myfaces-core-moduleReal-time download stats are indexed for npm and PyPI packages. This vulnerability affects Maven packages — download data is not available via public APIs for these ecosystems.
Description
In the default configuration, Apache MyFaces Core versions 2.2.0 to 2.2.13, 2.3.0 to 2.3.7, 2.3-next-M1 to 2.3-next-M4, and 3.0.0-RC1 use cryptographically weak implicit and explicit cross-site request forgery (CSRF) tokens. Due to that limitation, it is possible (although difficult) for an attacker to calculate a future CSRF token value and to use that value to trick a user into executing unwanted actions on an application.
Mitigation: Existing web.xml configuration parameters can be used to direct MyFaces to use SecureRandom for CSRF token generation:
org.apache.myfaces.RANDOM_KEY_IN_VIEW_STATE_SESSION_TOKEN=secureRandom org.apache.myfaces.RANDOM_KEY_IN_CSRF_SESSION_TOKEN=secureRandom org.apache.myfaces.RANDOM_KEY_IN_WEBSOCKET_SESSION_TOKEN=secureRandom
Affected Packages
| Ecosystem | Package | Vulnerable range | Fix |
|---|---|---|---|
| ☕Maven | org.apache.myfaces.core:myfaces-core-module | all versions | 2.0.25org.apache.myfaces.core:myfaces-core-module:2.0.25 |
| ☕Maven | org.apache.myfaces.core:myfaces-core-module | ≥ 2.1.0&&< 2.1.19 | 2.1.19org.apache.myfaces.core:myfaces-core-module:2.1.19 |
| ☕Maven | org.apache.myfaces.core:myfaces-core-module | ≥ 2.2.0&&< 2.2.14 | 2.2.14org.apache.myfaces.core:myfaces-core-module:2.2.14 |
| ☕Maven | org.apache.myfaces.core:myfaces-core-module | ≥ 2.3.0&&< 2.3.8 | 2.3.8org.apache.myfaces.core:myfaces-core-module:2.3.8 |
Affected Products
myfacesapacheoncommand insightnetappResearch use only. For defensive security, authorized penetration testing, and academic research only. Never execute exploit code against systems without explicit written authorization.
Detection & mitigation playbook
Open-source dependencyDetect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for org.apache.myfaces.core:myfaces-core-module, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update org.apache.myfaces.core:myfaces-core-module to 2.0.25 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2021-26296 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
Frequently Asked Questions
Is CVE-2021-26296 in your dependencies?
Find it across Maven, including transitive dependencies.