What is CVE-2021-26296?

CVE-2021-26296 is a high-severity vulnerability in Apache Myfaces, classified under Cross-Site Request Forgery (CSRF). CVSS score: 7.5/10. Published 2021-02-19.

How severe is CVE-2021-26296?

High severity. CVSS v3 base score is 7.5 out of 10.

Is CVE-2021-26296 known to be exploited?

2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.

CSRF in Apache Myfaces

CVE-2021-26296

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.

Vulnerability class: CSRF (Cross-Site Request Forgery)

Published 2021-02-19 · last modified 2026-06-17.

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H.

EPSS exploit prediction

EPSS: 0.029 (86.4th percentile), scored 2026-10-01.

Low probability of exploitation in the next 30 days, but still tracked. 86th percentile — 86.4% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS over last 30 days · oldest: 0.030 · newest: 0.029 · change: -0.001

Affected products

Apache Myfaces — versions 2.3, 3.0.0
Apache Software Foundation Myfaces Core — versions Apache MyFaces Core 2.2, Apache MyFaces Core 2.3, Apache MyFaces Core 2.3-next
NetApp Oncommand Insight

Weakness classification (CWE)

CWE-352 — Cross-Site Request Forgery (CSRF)

Public proof-of-concept exploits

References

lists.apache.org/thread.html/r2b73e2356c6155e9ec78fdd8f72a4fac12f3e588014f5f535… (Mailing List, Vendor Advisory)
seclists.org/fulldisclosure/2021/Feb/66 (mailing-list, Mailing List, Third Party Advisory)
packetstormsecurity.com/files/161484/Apache-MyFaces-2.x-Cross-Site-Request-Forg… (Exploit, VDB Entry, Third Party Advisory)
security.netapp.com/advisory/ntap-20210528-0007/ (Third Party Advisory)

Frequently asked questions

What is CVE-2021-26296?: CVE-2021-26296 is a high-severity vulnerability in Apache Myfaces, classified under Cross-Site Request Forgery (CSRF). CVSS score: 7.5/10. Published 2021-02-19.
How severe is CVE-2021-26296?: High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2021-26296 known to be exploited?: 2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.