Skip to main content

Outlook CVE-2023-35311

HIGH
Time-of-check Time-of-use (TOCTOU) Race Condition (CWE-367)
2023-07-11 secure@microsoft.com
8.8
CVSS 3.1 · NVD
View

Vulnerability Assessment

Weakness
CWE
ASVS 5.0
V15 - Secure Coding and Architecture TOCTOU prevention
Impact

CVSS score of 8.8 (HIGH). Attack characteristics: network attack vector, low complexity, no privileges required, user interaction required.

Exploit ScenarioDerived

This vulnerability can be exploited remotely over the network. Successful exploitation could compromise the high-severity affected system.

Act Now Prioritize within 24-48h. Why: In CISA KEV with patch available.
Exploited in the wild (CISA KEV) Patch available 15.5% exploitation probability (EPSS)

Get an e-mail when this CVE is exploited, patched or re-scored. Free account.

Alert me

AnalysisAI

Microsoft Outlook Security Feature Bypass Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely exploitable, no authentication required, low attack complexity.

RemediationAI

A vendor patch is available. Apply the latest security update as soon as possible. Apply vendor patches when available. Implement network segmentation and monitoring as interim mitigations.

Affects your stack

Find out whether the stacks and servers you run are on an affected version.

Checking this CVE against your own stacks and servers is part of the Basic plan and up.

Technical ContextAI · show details

This vulnerability is classified under CWE-367. Affected products include: Microsoft 365 Apps, Microsoft Office, Microsoft Office Long Term Servicing Channel, Microsoft Outlook.

Severity by source

NVD PRIMARY 8.8 HIGH
AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector
Network
Attack Complexity
Low
Privileges Required
None
User Interaction
Required
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

Lifecycle Timeline

2
Added to CISA KEV
Jul 14, 2026 - 04:22 CISA
CVE Published
Jul 11, 2023 - 18:15 cve.org
HIGH 8.8

DescriptionNVD

Microsoft Outlook Security Feature Bypass Vulnerability

Threat Intelligence Overview

EPSS Score
15.5%
Top 4% exploitable
Data Quality
4 sources
Confidence: Medium

How this decision was reached

The engine reads each signal below and applies a fixed list of rules from top to bottom. The first rule that matches sets the recommended action – like a statement, every line is shown.

SignalValue
Severity HIGH
CISA KEV Yes
Public POC No
EPSS 15.5%
Patch available Yes
Active threat Yes
Deciding rule
In CISA KEV with patch available
What every action level means
Emergency Immediate action required. Criteria: CRITICAL + in CISA KEV (actively exploited) without patch, OR CRITICAL + EPSS > 30% without patch, OR CRITICAL + active threat signals without patch.
Act Now Prioritize within 24-48h. Criteria: in KEV with patch available, OR CRITICAL + public POC, OR HIGH + EPSS > 10%, OR CRITICAL + active threat, OR any CRITICAL severity.
This Week Schedule remediation this week. Criteria: HIGH severity (CVSS 7.0-8.9). Patch within normal change window.
This Month Plan within 30 days. Criteria: MEDIUM severity (CVSS 4.0-6.9), lower exploitation probability. Include in regular patch cycle.
Monitor Track and reassess. Criteria: LOW severity (CVSS 0.1-3.9), minimal exploitation risk. No immediate action needed.

SSVC AssessmentENISA

SSVC Decision· derived
Out-of-Cycle
Exploitation· derived
Active
System Exposure· derived
Open
Automatable· derived
No
Human Impact· derived
High

Priority Score

110
Low Medium High Critical
KEV: +50
EPSS: +16
CVSS: +44
PoC: 0
Weaponized: 0
Threat intel: 0
Gov advisory: 0

Attack Technique

Authentication bypass attacks exploit flaws in the verification mechanisms that control access to systems and applications.

Affected Products (CPE)NVD

cpe:2.3:a:microsoft:365_apps:-:*:*:*:enterprise:*:*:*
cpe:2.3:a:microsoft:office:2019:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:office_long_term_servicing_channel:2021:*:*:*:*:*:*:*
cpe:2.3:a:microsoft:outlook:2013:-:-:*:-:-:*:*
cpe:2.3:a:microsoft:outlook:2013:sp1:*:*:rt:*:*:*
cpe:2.3:a:microsoft:outlook:2016:*:*:*:*:*:*:*
CVE-2026-96951 HIGH POC
8.8 Oct 13

Command injection in the Windows Shell lets remote, unauthenticated attackers bypass a Windows security feature and then

CVE-2013-3870 CRITICAL POC
9.3 Sep 11

Double free vulnerability in Microsoft Outlook 2007 SP3 and 2010 SP1 and SP2 allows remote attackers to execute arbitrar

CVE-2017-8506 HIGH
7.8 Jun 15

A remote code execution vulnerability exists in Microsoft Office when the software fails to properly handle objects in m

CVE-2024-42220 CRITICAL POC
9.1 Dec 18

A library injection vulnerability exists in Microsoft Outlook 16.83.3 for macOS. Rated critical severity (CVSS 9.1), thi

CVE-2023-33131 HIGH POC
8.8 Jun 14

Microsoft Outlook Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely ex

CVE-2018-0851 HIGH
8.8 Feb 15

Microsoft Office 2007 SP2, Microsoft Office Word Viewer, Microsoft Office 2010 SP2, Microsoft Office 2013 SP1 and RT SP1

CVE-2016-3278 HIGH
7.8 Jul 13

Microsoft Outlook 2010 SP2, 2013 SP1, 2013 RT SP1, and 2016 allows remote attackers to execute arbitrary code via a craf

CVE-2017-8507 HIGH
7.8 Jun 15

A remote code execution vulnerability exists in the way Microsoft Office software parses specially crafted email message

CVE-2024-30103 HIGH
8.8 Jun 11

Microsoft Outlook Remote Code Execution Vulnerability. Rated high severity (CVSS 8.8), this vulnerability is remotely ex

CVE-2020-37188 HIGH POC
7.5 Feb 11

SpotOutlook 1.2.6 contains a denial of service vulnerability in the registration name input field that allows attackers

CVE-2017-8663 HIGH
7.8 Aug 01

Microsoft Outlook 2007 SP3, Outlook 2010 SP2, Outlook 2013 SP1, Outlook 2013 RT SP1, and Outlook 2016 as packaged in Mic

CVE-2017-11776 HIGH
7.5 Oct 13

Microsoft Outlook 2016 allows an attacker to obtain the email content of a user, due to how Outlook 2016 discloses user

This site uses cookies essential for authentication and security. No tracking or analytics cookies are used. Privacy Policy