Raw vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:HCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2023-35311 is a high-severity Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367) vulnerability in Microsoft Outlook. Its CVSS base score is 8.8 (High).
Operationally, exploitation aligns with the MITRE ATT&CK technique Path Interception (T1034); ranked in the top 3% of CVEs by exploit likelihood; CISA has added it to the Known Exploited Vulnerabilities catalog.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
Microsoft Outlook contains a security feature bypass vulnerability tracked as CVE-2023-35311. The flaw, assigned CWE-367, resides in the client’s handling of messages or attachments and received a CVSS 3.1 score of 8.8 reflecting network attack vector, low complexity, no required privileges, and high impact on confidentiality, integrity, and availability.
An unauthenticated remote attacker can exploit the issue by sending a specially crafted message that triggers a race condition, allowing the security feature to be bypassed when the recipient interacts with the content. Successful exploitation can result in disclosure of sensitive information, modification of data, or full compromise of the Outlook process and underlying system.
Microsoft’s advisory directs customers to apply the security update released in July 2023; the vulnerability is also listed in CISA’s Known Exploited Vulnerabilities catalog, confirming that in-the-wild exploitation has been observed.
EPSS for the CVE rose sharply from a low baseline to a peak of 0.7572 on 28 October 2024 before receding, indicating that meaningful exploitation interest developed well after initial disclosure.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-39314
Vulnerability Data
Microsoft Outlook Security Feature Bypass Vulnerability
- CWE(s)
- KEV Date Added
- 11 July 2023
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V15.4.2V17.2.6
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
Timestamps meeting UTC or offset standards help identify TOCTOU issues through precise chronological reconstruction of check/use operations.
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 include coding standards and reviews that prevent TOCTOU race conditions.