CVE-2002-1973: Buffer overflow in CHttpServer::OnParseError in the ISAPI extension (Isapi.cpp) when built using Microsoft Fou

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HIGH 7.5WATCHLISTDOWNGRADEDOWNGRADE

CVE-2002-1973 is a high-severity flaw (CVSS 7.5) affecting foundation class library, badblue. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Buffer overflow in CHttpServer::OnParseError in the ISAPI extension (Isapi.cpp) when built using Microsoft Foundation Class (MFC) static libraries in Visual C++ 5.0, and 6.0 before SP3, as used in multiple products including BadBlue, allows remote attackers to cause a denial of service (access violation and crash) and possibly execute arbitrary code via a long query string that causes a parsing error.

Why this priority

High severity
EPSS top 1%: very likely to be exploited
Public exploit reference
On your watchlist

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

Risk facts

CVSS score	7.5 (High)
EPSS exploit chance	40.0% (top 1%)
CISA exploited list	No
Published	2002-12-31
Last modified	2026-06-16

Publisher (CNA): MITRE · Vendor: microsoft · working resources inc.

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

Am I affected?

Timeline

2002-12-31 05:00 UTCPublished CVE record published
2026-06-16 22:00 UTCUpdated Record last modified

microsoft foundation class library DOWNGRADE

Affected: 7.0

Fixed in: no fixed release known

Safe to downgrade to: a release before 7.0

1. Check installed version

apt-cache policy foundation-class-library || rpm -q foundation-class-library || foundation-class-library --version

2. No fixed release: DOWNGRADE to a release before 7.0 (Debian / Ubuntu)

apt-cache madison foundation-class-library sudo apt install foundation-class-library=<VERSION_BEFORE_7.0> sudo apt-mark hold foundation-class-library

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

dnf --showduplicates list foundation-class-library sudo dnf downgrade foundation-class-library-<VERSION_BEFORE_7.0> sudo dnf versionlock add foundation-class-library

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.

working resources inc. badblue DOWNGRADE

Affected: personal_1.7.3

Fixed in: no fixed release known

Safe to downgrade to: a release before personal_1.7.3

1. Check installed version

apt-cache policy badblue || rpm -q badblue || badblue --version

2. No fixed release: DOWNGRADE to a release before personal_1.7.3 (Debian / Ubuntu)

apt-cache madison badblue sudo apt install badblue=<VERSION_BEFORE_personal_1.7.3> sudo apt-mark hold badblue

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

dnf --showduplicates list badblue sudo dnf downgrade badblue-<VERSION_BEFORE_personal_1.7.3> sudo dnf versionlock add badblue

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.

Public exploits and detection

Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.

Exploit-DB: Microsoft Foundation Class Library 7.0 - ISAPI Buffer Overflow

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-2002-1973?

foundation class library: downgrade or apply the listed mitigation; badblue: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2002-1973 being exploited?

CVE-2002-1973 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-2002-1973 affect?

CVE-2002-1973 affects foundation class library, badblue. Severity is high (CVSS 7.5). Buffer overflow in CHttpServer::OnParseError in the ISAPI extension (Isapi.cpp) when built using Microsoft Foundation Class (MFC) static libraries in Visual C++ 5.0, and 6.0 before SP3, as used in multiple products including BadBlue, allows

How urgent is CVE-2002-1973?

Priority 61/100. High severity; EPSS top 1%: very likely to be exploited; Public exploit reference; On your watchlist

References

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