Exploited. On CISA's list since 2026-05-20.

Adobe Acrobat and Reader Heap-Based Buffer Overflow Vulnerability

CVE-2009-3459 · Adobe Acrobat and Reader · Published 2009-10-13

How bad would it be?

8.8 out of 10

CVSS rates it high.

How likely is it to be used?

87%

Estimated chance of exploitation in the next 30 days, among the top 1% of all scored flaws (EPSS, 2026-10-29).

Is it already being used?

Yes

CISA has seen it exploited in real attacks. For US government agencies the fix is deadline passed 149 days ago (2026-06-03).

What CISA says to do

Apply mitigations per vendor instructions, follow applicable BOD 22-01 guidance for cloud services, or discontinue use of the product if mitigations are unavailable.

Adobe Acrobat and Reader contain a heap-based buffer overflow vulnerability which could allow remote attackers to execute arbitrary code via a crafted PDF file that triggers memory corruption.

What the flaw is

Heap-based buffer overflow in Adobe Reader and Acrobat 7.x before 7.1.4, 8.x before 8.1.7, and 9.x before 9.2 allows remote attackers to execute arbitrary code via a crafted PDF file that triggers memory corruption, as exploited in the wild in October 2009. NOTE: some of these details are obtained from third party information.

From the NVD.

Fixes and advisories

blogs.adobe.comVendor Advisory
secunia.comVendor Advisory
www.adobe.comPatch, Vendor Advisory
www.vupen.comVendor Advisory
www.vupen.comVendor Advisory
blogs.adobe.comVendor Advisory

Learn this

Explore this week’s weaknesses and all learning topics

Understand the kind of weakness behind this flaw. These resources teach the weakness, rather than reproduce this specific CVE. Follow the vendor's advice above to fix the affected product.

Heap buffer overflow

A write runs past allocated heap storage and can damage neighbouring data.

CWE-122 · NVD record: 134c704f-9b21-4f2e-91b3-4a467353bcc0

Video course · Free course. C programming and memory concepts are useful; covers several weakness types.

Watch the course at OpenSecurityTraining2 How it is prevented

CWE-119 · CISA KEV; NVD record: nvd@nist.gov. We have not selected a close learning match for this label.

CWE is a catalogue of weakness types. Labels come from the sources shown and can differ or change. Resource matches reviewed 16 October 2026.

On SentryFeed

No story in the last 14 days has mentioned it.

Exploited flaws from CISA's KEV catalogue. Chance of exploitation from EPSS by FIRST. Descriptions and scores from the NVD. This product uses the NVD API but is not endorsed or certified by the NVD.