Is CVE-2009-0840 in the CISA KEV catalog?

No. CVE-2009-0840 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2009-0840?

CVE-2009-0840 has a CVSS v2 base score of 10.0 (HIGH).

What is the EPSS score for CVE-2009-0840?

CVE-2009-0840 has an EPSS score of 5.28% (92th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2009-0840?

Upgrade mapserver on debian 11 to 5.4.2-1 or later.

CVE & CISA-KEV Catalog

CVE-2009-0840

HIGHEPSS 92th pctl

10.0

CVSS v2

NVD

Description

Heap-based buffer underflow in the readPostBody function in cgiutil.c in mapserv in MapServer 4.x before 4.10.4 and 5.x before 5.2.2 allows remote attackers to have an unknown impact via a negative value in the Content-Length HTTP header.

CWE-119Buffer Overflow

How to fix

Remediation Available

mapserverDebian

Fixed in:5.4.2-1CVE-2009-0840

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v2 Vector

No CVSS vector data available.

Exploit Intelligence

5.28%probability of exploitation in 30 days

92ndpercentile

High risk: more likely to be exploited than 92% of all known CVEs.

References

Patch1

lists.osgeo.org

Exploit1

positronsecurity.com

Vendor Advisory1

trac.osgeo.org

Other references9

Related Vulnerabilities

Other CWE-119 (Buffer Overflow) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-4966	Critical	9.4	100%	KEV + Ransom	Fix
CVE-2017-11882	High	7.8	100%	KEV + Ransom	-
CVE-2020-0796	Critical	10.0	100%	KEV + Ransom	-
CVE-2008-4250	Critical	9.8	99%	KEV	-
CVE-2017-15944	Critical	9.8	98%	KEV	Fix
CVE-2015-0014	High	10.0	97%	-	-

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-04-23.