Microsoft Outlook Remote Code Execution Vulnerability
- Published
- Feb 13, 2024
- Updated
- Aug 10, 2026
- EPSS
- 94.7% · 100th percentile
- CWE
- CWE-20
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Report tools
Action score
97
Now
Patch today or shut off access.
- CVSS
- 39 / 40 · 9.8 / 10
- CISA KEV
- 30 / 30 · Listed
- EPSS
- 28 / 30 · 94.7%
CISA SSVC decision
- Exploitation
- active
- Automatable
- yes
- Technical impact
- total
Vulnrichment: CISA's decision-tree inputs.
CNA vs NVD score
- NVD
- —
- CNA · microsoft
- 9.8
- NVD has not scored this yet; the score shown is the CNA’s.
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H/E:U/RL:O/RC:C
The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.
Actively exploited in the wild
CISA added this to its Known Exploited Vulnerabilities catalog on Feb 6, 2025. That signals real attacks, not theory.
Remediation deadline for government agencies: Feb 27, 2025.
Affected systems
| Vendor | Product | CPE |
|---|---|---|
| microsoft | 365 apps | cpe:2.3:a:microsoft:365_apps |
| microsoft | office 2016 | cpe:2.3:a:microsoft:office_2016 |
| microsoft | office 2019 | cpe:2.3:a:microsoft:office_2019 |
| microsoft | office long term servicing channel | cpe:2.3:a:microsoft:office_long_term_servicing_channel |
Affected versions
NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.
- microsoft 365 appsall versions
- microsoft office 2016all versions
- microsoft office 2019all versions
- microsoft office long term servicing channel2021
Versions reported by the vendor
Affected version ranges reported by the assigning authority (microsoft). Independent of NVD's CPE analysis and usually ahead of it.
Microsoft Microsoft 365 Apps for Enterprise
- 16.0.1 and later · before https://aka.ms/OfficeSecurityReleasesaffected
Microsoft Microsoft Office 2016
- 16.0.0 and later · before 16.0.5435.1001affected
Microsoft Microsoft Office 2019
- 19.0.0 and later · before https://aka.ms/OfficeSecurityReleasesaffected
Microsoft Microsoft Office LTSC 2021
- 16.0.1 and later · before https://aka.ms/OfficeSecurityReleasesaffected
Same product
microsoft: all recordsOther highest-scoring records for the same primary product.
- CVE-2023-23397Microsoft Outlook Elevation of Privilege VulnerabilityKEV98Now
- CVE-2026-21509Microsoft Office Security Feature Bypass VulnerabilityKEV82Now
- CVE-2021-42292Microsoft Excel Security Feature Bypass VulnerabilityKEV74This week
- CVE-2023-35311Microsoft Outlook Security Feature Bypass VulnerabilityKEV70This week
- CVE-2024-38189Microsoft Project Remote Code Execution VulnerabilityKEV67This week
- CVE-2023-21715Microsoft Publisher Security Feature Bypass VulnerabilityKEV63This week
Remediation
Which version to upgrade to
Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.
No fix version is recorded for this entry. Check the references for vendor advisories.
Exploit status
Weaponized
A ready exploit tool or active in-the-wild use is known for this vulnerability. This should be your top priority.
Evidence
- Proof-of-concept repository on GitHub ×42
Noroxi does not host or link to exploit code. Metasploit module names and Nuclei template ids are shown (names, not code); Exploit-DB entries and PoC repositories are given as counts only.
| Source | Kind | Date |
|---|---|---|
| Proof-of-concept repository on GitHub | stars:156 | 2024-02-15 |
| Proof-of-concept repository on GitHub | stars:776 | 2024-02-16 |
| Proof-of-concept repository on GitHub | stars:17 | 2024-02-16 |
| Proof-of-concept repository on GitHub | stars:285 | 2024-02-17 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-02-19 |
| Proof-of-concept repository on GitHub | stars:5 | 2024-02-20 |
| Proof-of-concept repository on GitHub | stars:4 | 2024-02-23 |
| Proof-of-concept repository on GitHub | stars:2 | 2024-02-29 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-04-13 |
| Proof-of-concept repository on GitHub | stars:2 | 2024-05-03 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-05-11 |
| Proof-of-concept repository on GitHub | stars:0 | 2024-06-18 |
Research context
For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.
Timeline
From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.
- Published
- First PoC+1 d
- CISA KEV+358 d
- TodaySep 29, 2026+959 d
FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).
Patch and commit links
Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.
No commit or PR link among the references.
Credits
All researchersFinders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.
No credits in the CNA record.
Variant candidates
Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.
- CVE-2023-23397336 days apartMicrosoft Outlook Elevation of Privilege VulnerabilityKEV98Now
- CVE-2024-38189182 days apartMicrosoft Project Remote Code Execution VulnerabilityKEV67This week
- CVE-2023-36761154 days apartMicrosoft Word Information Disclosure VulnerabilityKEV62This week
- CVE-2024-38021147 days apartMicrosoft Outlook Remote Code Execution Vulnerability36Monitor
- CVE-2024-49033273 days apartMicrosoft Word Security Feature Bypass Vulnerability31Monitor
- CVE-2023-36762154 days apartMicrosoft Word Remote Code Execution Vulnerability29Monitor
Chain candidates
An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.
—
Bug bounty scope
No known public program.
Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).
Technical details
Attack conditions
- Anyone who can reach it over the internet can trigger it.
- No account or password is required.
- No user action is required.
- No special conditions are required; it is repeatable.
If successful
- Confidentiality
- high · data can be read
- Integrity
- high · data or configuration can be modified
- Availability
- high · the service can be disrupted
- Attack vector
- Network
- Attack complexity
- Low
- Privileges required
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality impact
- High
- Integrity impact
- High
- Availability impact
- High
Weakness class (CWE)
CWE-20 · Improper Input ValidationCVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
nvd-secondary
Attack context
MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.
Attack patterns (CAPEC)
- Buffer Overflow via Environment VariablesCAPEC-10likelihood: High · High
- Server Side Include (SSI) InjectionCAPEC-101likelihood: High · High
- Cross Zone ScriptingCAPEC-104likelihood: Medium · High
- Command Line Execution through SQL InjectionCAPEC-108likelihood: Low · Very High
- Object Relational Mapping InjectionCAPEC-109likelihood: Low · High
- SQL Injection through SOAP Parameter TamperingCAPEC-110likelihood: High · Very High
- Double EncodingCAPEC-120likelihood: Low · Medium
- Subverting Environment Variable ValuesCAPEC-13likelihood: High · Very High
ATT&CK techniques
- Obfuscated Files or InformationT1027
- Masquerading: Invalid Code SignatureT1036.001
- Steal Web Session CookieT1539
- Subvert Trust Controls: Code SigningT1553.002
- Impair Defenses:Impair Command History LoggingT1562.003
- Hijack Execution Flow:Dynamic Linker HijackingT1574.006
- Hijack Execution Flow:Path Interception by PATH Environment VariableT1574.007
Noroxi analysis
No Noroxi analysis for this record yet
We don't hand-write analysis for all 385,000+ vulnerabilities; that wouldn't be honest. For notable, high-impact vulnerabilities our team writes the mechanism, detection and remediation steps.
We use this product, ask for helpChange log
No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.
References
- msrc.microsoft.com/update-guide/vulnerability/CVE-2024-21413
- research.checkpoint.com/2024/the-risks-of-the-monikerlink-bug-in-microsoft-outlook-and-the-big-picture/
- www.vicarius.io/vsociety/posts/cve-2024-21413-critical-monikerlink-vulnerability-affecting-microsoft-outlook-mitigation-script
- www.cisa.gov/known-exploited-vulnerabilities-catalog?field_cve=CVE-2024-21413
Vendor advisories and official records. Exploit/PoC links are deliberately left out.