Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HSummary
CVE-2026-33373 is a high-severity CSRF (CWE-352) vulnerability in Synacor Zimbra Collaboration Suite. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 10th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to AC-3 (Access Enforcement) and SC-23 (Session Authenticity) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-33373 is a Cross-Site Request Forgery (CSRF) vulnerability, classified under CWE-352, affecting Zimbra Collaboration Suite (ZCS) versions 10.0 and 10.1, specifically in the Zimbra Web Client. The issue arises because authentication tokens issued during certain account state transitions, such as enabling two-factor authentication or changing a password, lack CSRF protection. While these tokens are active, authenticated SOAP requests that trigger token generation or state changes can bypass CSRF validation, with a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H).
An unauthenticated attacker (PR:N) can exploit this vulnerability by tricking an authenticated victim into submitting crafted requests through social engineering or malicious websites, requiring user interaction (UI:R). Successful exploitation enables the attacker to perform sensitive account actions on the victim's behalf, such as disabling two-factor authentication, potentially leading to high confidentiality, integrity, and availability impacts.
Zimbra advisories recommend upgrading to patched versions, including ZCS 10.0.18 and 10.1.13, which address the issue through security fixes that ensure CSRF protection is consistently enforced for all issued authentication tokens. Additional details are available in the Zimbra Security Center and Responsible Disclosure Policy on their wiki.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-17106
Vulnerability Data
An 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…
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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.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V3.3.2V3.5.1V10.2.1
Mitigating Controls (NIST 800-53 r5) AI
Access enforcement requires verifying that state-changing requests originate from the authenticated user rather than a forged cross-site source.
Protecting session authenticity prevents attackers from replaying or forging authenticated requests via the victim's browser.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Secure SDLC practices directly require anti-CSRF controls such as tokens or SameSite attributes.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
By denying access to phishing or malicious sites, the control lowers the likelihood that a user will be tricked into submitting a forged request that performs an unintended action on another site.
Contextual intelligence about emerging CSRF toolkits can be translated into updated anti-CSRF token or same-site policy configurations across applications.