How severe is CVE-2008-5911?

CVE-2008-5911 has a CVSS 2.0 base score of 10.0, rated critical severity.

Is CVE-2008-5911 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2008-5911?

CVE-2008-5911 primarily affects Realnetworks Helix Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2008-5911?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.

When was CVE-2008-5911 published?

CVE-2008-5911 was published on 2009-01-20 and last updated on 2026-06-16.

CVE-2008-5911

CVE-2008-5911 is a critical-severity vulnerability in Realnetworks Helix Server with a CVSS 2.0 base score of 10.0. 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-119.

Key facts

Severity: Critical (CVSS 2.0 base score 10.0)
EPSS exploit prediction: 6% (93rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-119
Affected product: Realnetworks Helix Server
Published: 2009-01-20
Last modified: 2026-06-16

Description

Multiple buffer overflows in RealNetworks Helix Server and Helix Mobile Server 11.x before 11.1.8 and 12.x before 12.0.1 allow remote attackers to (1) cause a denial of service via three crafted RTSP SETUP commands, or execute arbitrary code via (2) an NTLM authentication request with malformed base64-encoded data, (3) an RTSP DESCRIBE command, or (4) a DataConvertBuffer request.

Frequently asked questions

What is CVE-2008-5911?: Multiple buffer overflows in RealNetworks Helix Server and Helix Mobile Server 11.x before 11.1.8 and 12.x before 12.0.1 allow remote attackers to (1) cause a denial of service via three crafted RTSP SETUP commands, or execute arbitrary code via (2) an NTLM authentication request with malformed base64-encoded data, (3) an RTSP DESCRIBE command, or (4) a DataConvertBuffer request.
How severe is CVE-2008-5911?: CVE-2008-5911 has a CVSS 2.0 base score of 10.0, rated critical severity.
Is CVE-2008-5911 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 6% (93rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2008-5911?: CVE-2008-5911 primarily affects Realnetworks Helix Server. In total, 4 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2008-5911?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its critical severity, prioritise patching exposed systems.
When was CVE-2008-5911 published?: CVE-2008-5911 was published on 2009-01-20 and last updated on 2026-06-16.

References

Affected products (4)

cpe:2.3:a:realnetworks:helix_server:11.0:*:*:*:*:*:*:*
cpe:2.3:a:realnetworks:helix_server:12.0.0:*:*:*:*:*:*:*
cpe:2.3:a:realnetworks:helix_server_mobile:11.0:*:*:*:*:*:*:*
cpe:2.3:a:realnetworks:helix_server_mobile:12.0.0:*:*:*:*:*:*:*

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