How severe is CVE-2009-0023?

CVE-2009-0023 has a CVSS 2.0 base score of 4.3, rated medium severity.

Is CVE-2009-0023 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (94th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-0023?

CVE-2009-0023 primarily affects Apache Apr-util. In total, 22 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-0023?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2009-0023 published?

CVE-2009-0023 was published on 2009-06-08 and last updated on 2026-06-16.

CVE-2009-0023

CVE-2009-0023 is a medium-severity vulnerability in Apache Apr-util with a CVSS 2.0 base score of 4.3. It is not currently listed as actively exploited by CISA, and its EPSS exploit-prediction score is low. The underlying weakness is classified as CWE-119.

Key facts

Severity: Medium (CVSS 2.0 base score 4.3)
EPSS exploit prediction: 9% (94th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Apache Apr-util
Published: 2009-06-08
Last modified: 2026-06-16

Description

The apr_strmatch_precompile function in strmatch/apr_strmatch.c in Apache APR-util before 1.3.5 allows remote attackers to cause a denial of service (daemon crash) via crafted input involving (1) a .htaccess file used with the Apache HTTP Server, (2) the SVNMasterURI directive in the mod_dav_svn module in the Apache HTTP Server, (3) the mod_apreq2 module for the Apache HTTP Server, or (4) an application that uses the libapreq2 library, which triggers a heap-based buffer underflow.

Frequently asked questions

What is CVE-2009-0023?: The apr_strmatch_precompile function in strmatch/apr_strmatch.c in Apache APR-util before 1.3.5 allows remote attackers to cause a denial of service (daemon crash) via crafted input involving (1) a .htaccess file used with the Apache HTTP Server, (2) the SVNMasterURI directive in the mod_dav_svn module in the Apache HTTP Server, (3) the mod_apreq2 module for the Apache HTTP Server, or (4) an application that uses the libapreq2 library, which triggers a heap-based buffer underflow.
How severe is CVE-2009-0023?: CVE-2009-0023 has a CVSS 2.0 base score of 4.3, rated medium severity.
Is CVE-2009-0023 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 9% (94th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-0023?: CVE-2009-0023 primarily affects Apache Apr-util. In total, 22 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-0023?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-0023 published?: CVE-2009-0023 was published on 2009-06-08 and last updated on 2026-06-16.

References

Affected products (22)

cpe:2.3:a:apache:apr-util:*:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:0.9.1:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:0.9.2:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:0.9.3:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:0.9.4:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:0.9.5:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.0:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.0.1:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.0.2:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.1.0:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.1.1:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.1.2:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.2.1:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.2.2:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.2.6:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.2.7:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.2.8:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.3.0:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.3.1:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.3.2:*:*:*:*:*:*:*
cpe:2.3:a:apache:apr-util:1.3.3:*:*:*:*:*:*:*
cpe:2.3:a:apache:http_server:*:*:*:*:*:*:*:*

More vulnerabilities in Apache Apr-util

CVE-2009-2412 — Critical (CVSS 10.0): Multiple integer overflows in the Apache Portable Runtime (APR) library and the Apache Portable Utility library (aka…
CVE-2009-1955 — High (CVSS 7.5): The expat XML parser in the apr_xml_* interface in xml/apr_xml.c in Apache APR-util before 1.3.7, as used in the…
CVE-2009-1956 — Medium (CVSS 6.4): Off-by-one error in the apr_brigade_vprintf function in Apache APR-util before 1.3.5 on big-endian platforms allows…
CVE-2010-1623 — Medium (CVSS 5.0): Memory leak in the apr_brigade_split_line function in buckets/apr_brigade.c in the Apache Portable Runtime Utility…
CVE-2011-1928 — Medium (CVSS 4.3): The fnmatch implementation in apr_fnmatch.c in the Apache Portable Runtime (APR) library 1.4.3 and 1.4.4, and the…

All CVEs affecting Apache Apr-util →

Other CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities

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CVE-2026-2776 — Critical (CVSS 10.0): Sandbox escape due to incorrect boundary conditions in the Telemetry component in External Software. This vulnerability…
CVE-2025-1866 — Critical (CVSS 10.0): Improper Restriction of Operations within the Bounds of a Memory Buffer vulnerability in warmcat libwebsockets allows…
CVE-2022-27625 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2022-27624 — Critical (CVSS 10.0): A vulnerability regarding improper restriction of operations within the bounds of a memory buffer is found in the…
CVE-2020-11896 — Critical (CVSS 10.0): The Treck TCP/IP stack before 6.0.1.66 allows Remote Code Execution, related to IPv4 tunneling.

Browse all CWE-119 (Improper Restriction of Operations within the Bounds of a Memory Buffer) vulnerabilities →

Threat intelligence

Threat-intel indicators referencing this CVE:

222.99.52.202 (ipv4-addr)
41.224.62.206 (ipv4-addr)
218.4.156.254 (ipv4-addr)
171.100.156.38 (ipv4-addr)