CVE-2026-33373
Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.
NVD · uneditedAn issue was discovered in Zimbra Collaboration (ZCS) 10.0 and 10.1. A Cross-Site Request Forgery (CSRF) vulnerability exists in Zimbra Web Client due to the issuance of authentication tokens without CSRF protection during certain account state transitions. Specifically, tokens generated after operations such as enabling two-factor authentication or changing a password may lack CSRF enforcement. While such a token is active, authenticated SOAP requests that trigger token generation or state changes can be performed without CSRF validation. An attacker could exploit this by inducing a victim to submit crafted requests, potentially allowing sensitive account actions such as disabling two-factor authentication. The issue is mitigated by ensuring CSRF protection is consistently enforced for all issued authentication tokens.
Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.
dbcve analysis · moderate confidenceThis is a CSRF vulnerability in Zimbra Collaboration (ZCS) 10.0/10.1 where authentication tokens issued after certain account state transitions (enabling 2FA, changing password) lack CSRF protection. Attackers can exploit this by tricking authenticated users into submitting crafted requests that perform sensitive actions like disabling two-factor authentication.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data>= 10.0.0, < 10.0.18>= 10.1.0, < 10.1.13CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.
From the vector- Attack vector
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- Required
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.
dbcve checksWork through these to decide whether this CVE applies to you.
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Check Zimbra Collaboration versionRun 'zmcontrol -v' or check /opt/zimbra/.version from the Zimbra server to determine the installed version numberAffected if The installed version falls within >= 10.0.0 and < 10.0.18, or >= 10.1.0 and < 10.1.13
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Verify SOAP API accessibilityConfirm that the Zimbra SOAP endpoint (typically at /service/soap) is exposed and accessible from untrusted networksAffected if SOAP API is externally accessible without additional access controls
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Inspect CSRF protection configurationCheck Zimbra's configuration for CSRF token enforcement: review zimbraCsrfAllowedRefererDomains and zimbraCsrfTokenMaxAge settings in 'zmprov gcf' outputAffected if CSRF protection settings are absent, disabled, or do not cover account state transition endpoints
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Check for vulnerable token issuanceReview server logs or network traces for authentication tokens issued during 2FA enablement or password change operations - examine if these tokens include CSRF token validationAffected if Tokens generated during account state transitions do not require CSRF token validation before use in SOAP requests
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Test token reuse in SOAP requestsUsing an authenticated session, make a SOAP request to modify account settings (such as disabling 2FA) and observe if the request succeeds without a CSRF token headerAffected if Authenticated SOAP requests succeed without CSRF token validation, indicating the vulnerability is present
A user is affected if they run a Zimbra version between 10.0.0-10.0.17 or 10.1.0-10.1.12 and their SOAP API accepts authenticated requests without CSRF token validation, particularly during account state transitions.
Generated from the published advisory. Verify against your own configuration.
Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.
dbcve · scoped10.0.1810.1.13
Ensure CSRF protection is consistently enforced for all authentication tokens generated during account state transitions. Implement CSRF token validation for SOAP requests that trigger token generation or sensitive account changes.
Upgrade to Zimbra 10.0.18 (if on 10.0.x) or 10.1.13 (if on 10.1.x)
- 1. Identify current Zimbra Collaboration Suite version by running: zimbra@zimbra:~$ zmcontrol -v
- 2. Review the upgrade path for your current version (10.0.x or 10.1.x)
- 3. Create a full backup of the Zimbra mailbox and configuration data
- 4. Schedule a maintenance window for the upgrade
- 5. Download the fixed version: 10.0.18 (for 10.0.x branch) or 10.1.13 (for 10.1.x branch) from Zimbra's official download portal
- 6. Run the installation upgrade as the Zimbra user: ./install.sh -s (or follow standard upgrade procedures)
- 7. After upgrade, verify the Zimbra services started correctly: zmcontrol status
- 8. Confirm the fix by checking that CSRF tokens are now properly enforced for all authentication token issuances, particularly after enabling two-factor authentication or changing passwords
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation16.0 h
- Testing8.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-33373 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-33373 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
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