CVE-2012-1891: Heap-based buffer overflow in Microsoft Data Access Components (MDAC) 2.8 SP1 and SP2 and Windows Data Access

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CRITICAL 9.8REMOTEWATCHLISTDOWNGRADEDOWNGRADE

CVE-2012-1891 is a critical-severity flaw (CVSS 9.8) affecting data access components, windows data access components. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Heap-based buffer overflow in Microsoft Data Access Components (MDAC) 2.8 SP1 and SP2 and Windows Data Access Components (WDAC) 6.0 allows remote attackers to execute arbitrary code via crafted XML data that triggers access to an uninitialized object in memory, aka "ADO Cachesize Heap Overflow RCE Vulnerability."

Why this priority

Critical severity
EPSS top 2%: very likely to be exploited
Remotely exploitable, no login, no user action
On your watchlist

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	29.4% (top 2%)
CISA exploited list	No
Weakness	CWE-119, CWE-908
Published	2012-07-10
Last modified	2026-06-16

Publisher (CNA): Microsoft Corporation · Vendor: microsoft

Last updated 2026-06-16 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2012-07-10 21:55 UTCPublished CVE record published
2026-06-16 23:40 UTCUpdated Record last modified

microsoft data access components DOWNGRADE

Affected: 2.8 sp1 · 2.8 sp2

Fixed in: no fixed release known

Safe to downgrade to: a release before 2.8

1. Check installed version

apt-cache policy data-access-components || rpm -q data-access-components || data-access-components --version

2. No fixed release: DOWNGRADE to a release before 2.8 (Debian / Ubuntu)

apt-cache madison data-access-components sudo apt install data-access-components=<VERSION_BEFORE_2.8> sudo apt-mark hold data-access-components

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list data-access-components sudo dnf downgrade data-access-components-<VERSION_BEFORE_2.8> sudo dnf versionlock add data-access-components

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

microsoft windows data access components DOWNGRADE

Affected: 6.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 6.0

1. Check installed version

apt-cache policy windows-data-access-components || rpm -q windows-data-access-components || windows-data-access-components --version

2. No fixed release: DOWNGRADE to a release before 6.0 (Debian / Ubuntu)

apt-cache madison windows-data-access-components sudo apt install windows-data-access-components=<VERSION_BEFORE_6.0> sudo apt-mark hold windows-data-access-components

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list windows-data-access-components sudo dnf downgrade windows-data-access-components-<VERSION_BEFORE_6.0> sudo dnf versionlock add windows-data-access-components

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2012-1891?

data access components: downgrade or apply the listed mitigation; windows data access components: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2012-1891 being exploited?

CVE-2012-1891 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2012-1891 affect?

CVE-2012-1891 affects data access components, windows data access components. Severity is critical (CVSS 9.8). Heap-based buffer overflow in Microsoft Data Access Components (MDAC) 2.8 SP1 and SP2 and Windows Data Access Components (WDAC) 6.0 allows remote attackers to execute arbitrary code via crafted XML data that triggers access to an uninitiali

How urgent is CVE-2012-1891?

Priority 69/100. Critical severity; EPSS top 2%: very likely to be exploited; Remotely exploitable, no login, no user action; On your watchlist

Software pages

Windows vulnerabilities

Related CVEs

CVE-2011-0027 HIGH 9.3 DOWNGRADE DOWNGRADE Microsoft Data Access Components (MDAC) 2.8 SP1 and SP2, and Windows Data Access Components (WDAC) 6.0, does n
CVE-2011-0026 HIGH 9.3 DOWNGRADE DOWNGRADE Integer signedness error in the SQLConnectW function in an ODBC API (odbc32.dll) in Microsoft Data Access Comp
CVE-2006-5559 HIGH 9.3 DOWNGRADE The Execute method in the ADODB.Connection 2.7 and 2.8 ActiveX control objects (ADODB.Connection.2.7 and ADODB
CVE-2006-0003 MEDIUM 5.1 DOWNGRADE Unspecified vulnerability in the RDS.Dataspace ActiveX control, which is contained in ActiveX Data Objects (AD
CVE-2003-0903 HIGH 10.0 DOWNGRADE Buffer overflow in a component of Microsoft Data Access Components (MDAC) 2.5 through 2.8 allows remote attack

References

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