What is the CVSS score of CVE-2015-2521?

CVE-2015-2521 has a CVSS 2.0 base score of 9.3 (Critical). CVSS vector: AV:N/AC:M/Au:N/C:C/I:C/A:C. EPSS exploitation probability: 69.2%.

Is there a public PoC exploit available for CVE-2015-2521?

Yes, a public proof-of-concept exploit is available for CVE-2015-2521. Prioritise patching immediately. EPSS: 69.2%.

Excel CVE-2015-2521

CRITICAL

Buffer Overflow (CWE-119)

2015-09-09 secure@microsoft.com

RCE Buffer Overflow Microsoft Excel Excel Viewer Office Compatibility Pack

9.3

CVSS 2.0 · NVD

View

Vulnerability Assessment

Weakness	CWE CWE-119 ASVS 5.0 V15 - Secure Coding and Architecture Bounds checking, buffer size validation MITRE ATT&CK 2 techniques across 2 tactics: Execution, Privilege Escalation The technique list with ATT&CK links and the kill-chain view is part of the Basic plan and up. Sign in to read
Impact	CVSS score of 9.3 (CRITICAL). Attack characteristics: network attack vector, M complexity. Public proof-of-concept exploit code is available. EPSS exploitation probability: 69.18%.
Exploit ScenarioDerived	A remote attacker could corrupt memory to execute arbitrary code or crash the application by sending crafted requests to the affected application.

Emergency Immediate action required. Why: CRITICAL + EPSS > 30%, no patch available.

No patch listed yet 69.2% exploitation probability (EPSS)

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AnalysisAI

Microsoft Excel 2007 SP3, Excel 2010 SP2, Office Compatibility Pack SP3, and Excel Viewer allow remote attackers to execute arbitrary code via a crafted Office document, aka "Microsoft Office Memory. Rated critical severity (CVSS 9.3), this vulnerability is remotely exploitable. Public exploit code available and EPSS exploitation probability 69.2%.

RemediationAI

No vendor patch is available at time of analysis. Monitor vendor advisories for updates. Use memory-safe languages or bounds-checking. Enable ASLR, DEP/NX, stack canaries. Use safe string functions.

Affects your stack

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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 as Buffer Overflow (CWE-119), which allows attackers to corrupt memory to execute arbitrary code or crash the application. Microsoft Excel 2007 SP3, Excel 2010 SP2, Office Compatibility Pack SP3, and Excel Viewer allow remote attackers to execute arbitrary code via a crafted Office document, aka "Microsoft Office Memory Corruption Vulnerability." Affected products include: Microsoft Excel, Microsoft Excel Viewer, Microsoft Office Compatibility Pack.

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Exploit and PoC references, threat intelligence from 22 sources

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Severity by source

NVD PRIMARY 9.3 CRITICAL

AV:N/AC:M/Au:N/C:C/I:C/A:C

Primary rating from NVD · only source for this CVE.

CVSS VectorNVD

Attack Vector

Network

Attack Complexity

Confidentiality

Integrity

Availability

DescriptionCVE.org

Threat Intelligence Overview

Threat Score

5.4/10

Composite threat intelligence

EPSS Score

69.2%

Top 1% exploitable

Exploit

POC

Public exploit code exists

Data Quality

4 sources

Confidence: Medium

NVD

CVE.org

EPSS

Exploit-DB

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 CRITICAL

CISA KEV No

Public POC Yes

EPSS 69.2%

Patch available No

Active threat Yes

Deciding rule

CRITICAL + EPSS > 30%, no 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

Scheduled

Exploitation· derived

Poc

System Exposure· derived

Open

Automatable· derived

Human Impact· derived

Medium

Priority Score

135

Low Medium High Critical

KEV: 0

EPSS: +69

CVSS: +46

PoC: +20

Weaponized: 0

Threat intel: 0

Gov advisory: 0

Attack Technique

Buffer Overflow HIGH

A buffer overflow occurs when a program writes more data to a memory buffer than it was allocated to hold, causing the excess data to spill into adjacent memory regions.

Remote Code Execution CRITICAL

Remote Code Execution represents the critical moment when an attacker successfully runs arbitrary code on a target system without physical access.