How severe is CVE-2009-4086?

CVE-2009-4086 has a CVSS 2.0 base score of 5.0, rated medium severity.

Is CVE-2009-4086 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2009-4086?

CVE-2009-4086 primarily affects Javascript Xerver Http Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2009-4086?

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

When was CVE-2009-4086 published?

CVE-2009-4086 was published on 2009-11-29 and last updated on 2026-06-16.

CVE-2009-4086

CVE-2009-4086 is a medium-severity vulnerability in Javascript Xerver Http Server with a CVSS 2.0 base score of 5.0. 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-20.

Key facts

Severity: Medium (CVSS 2.0 base score 5.0)
EPSS exploit prediction: 5% (91st percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Javascript Xerver Http Server
Published: 2009-11-29
Last modified: 2026-06-16

Description

CRLF injection vulnerability in Xerver HTTP Server 4.31 and 4.32 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via certain byte sequences at the end of a URL. NOTE: some of these details are obtained from third party information.

Frequently asked questions

What is CVE-2009-4086?: CRLF injection vulnerability in Xerver HTTP Server 4.31 and 4.32 allows remote attackers to inject arbitrary HTTP headers and conduct HTTP response splitting attacks via certain byte sequences at the end of a URL. NOTE: some of these details are obtained from third party information.
How severe is CVE-2009-4086?: CVE-2009-4086 has a CVSS 2.0 base score of 5.0, rated medium severity.
Is CVE-2009-4086 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 5% (91st percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2009-4086?: CVE-2009-4086 primarily affects Javascript Xerver Http Server. In total, 2 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2009-4086?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2009-4086 published?: CVE-2009-4086 was published on 2009-11-29 and last updated on 2026-06-16.

References

Affected products (2)

cpe:2.3:a:javascript:xerver_http_server:4.31:*:*:*:*:*:*:*
cpe:2.3:a:javascript:xerver_http_server:4.32:*:*:*:*:*:*:*

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