SSRF in Zimbra Collaboration

CVE-2021-35209

An issue was discovered in ProxyServlet.java in the /proxy servlet in Zimbra Collaboration Suite 8.8 before 8.8.15 Patch 23 and 9.x before 9.0.0 Patch 16. The value of the X-Host header overwrites the value of the Host header in proxied re…

Vulnerability class: SSRF (Server-Side Request Forgery)

EPSS: 0.030 (85.7th percentile) — read the EPSS interpretation.

CVSS v3 metric

CVSS v3 base score 9.8 (Critical). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2021-35209?
CVE-2021-35209 is a critical-severity vulnerability in Zimbra Collaboration, classified under Server-Side Request Forgery (SSRF). CVSS score: 9.8/10. Published 2021-07-02.
How severe is CVE-2021-35209?
Critical severity. CVSS v3 base score is 9.8 out of 10.
Is CVE-2021-35209 known to be exploited?
2 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.