How severe is CVE-2015-6391?

CVE-2015-6391 has a CVSS 2.0 base score of 7.8, rated high severity.

Is CVE-2015-6391 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2015-6391?

CVE-2015-6391 primarily affects Cisco Unified Sip Phone 3900 Firmware. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2015-6391?

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

When was CVE-2015-6391 published?

CVE-2015-6391 was published on 2015-12-05 and last updated on 2026-06-17.

CVE-2015-6391

CVE-2015-6391 is a high-severity vulnerability in Cisco Unified Sip Phone 3900 Firmware with a CVSS 2.0 base score of 7.8. 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-399.

Key facts

Severity: High (CVSS 2.0 base score 7.8)
EPSS exploit prediction: 2% (77th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-399
Affected product: Cisco Unified Sip Phone 3900 Firmware
Published: 2015-12-05
Last modified: 2026-06-17

Description

Cisco Unified SIP 3905 phones allow remote attackers to cause a denial of service (resource consumption and functionality loss) via a large amount of network traffic, aka Bug ID CSCuh51331.

Frequently asked questions

What is CVE-2015-6391?: Cisco Unified SIP 3905 phones allow remote attackers to cause a denial of service (resource consumption and functionality loss) via a large amount of network traffic, aka Bug ID CSCuh51331.
How severe is CVE-2015-6391?: CVE-2015-6391 has a CVSS 2.0 base score of 7.8, rated high severity.
Is CVE-2015-6391 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (77th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2015-6391?: CVE-2015-6391 primarily affects Cisco Unified Sip Phone 3900 Firmware. In total, 7 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2015-6391?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround. Given its high severity, prioritise patching exposed systems.
When was CVE-2015-6391 published?: CVE-2015-6391 was published on 2015-12-05 and last updated on 2026-06-17.

References

Affected products (7)

cpe:2.3:o:cisco:unified_sip_phone_3900_firmware:8.1\(1b\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_sip_phone_3900_firmware:8.1\(2\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_sip_phone_3900_firmware:8.1\(2\)sr1:*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_sip_phone_3900_firmware:8.1\(3\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_sip_phone_3900_firmware:8.1\(4\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_sip_phone_3900_firmware:9.2\(1\):*:*:*:*:*:*:*
cpe:2.3:o:cisco:unified_sip_phone_3900_firmware:9.2\(2\):*:*:*:*:*:*:*

Other CWE-399 (Resource Management Errors) vulnerabilities

CVE-2015-8104 — Critical (CVSS 10.0): The KVM subsystem in the Linux kernel through 4.2.6, and Xen 4.3.x through 4.6.x, allows guest OS users to cause a…
CVE-2015-0339 — Critical (CVSS 10.0): Adobe Flash Player before 13.0.0.277 and 14.x through 17.x before 17.0.0.134 on Windows and OS X and before…
CVE-2015-0335 — Critical (CVSS 10.0): Adobe Flash Player before 13.0.0.277 and 14.x through 17.x before 17.0.0.134 on Windows and OS X and before…
CVE-2015-0333 — Critical (CVSS 10.0): Adobe Flash Player before 13.0.0.277 and 14.x through 17.x before 17.0.0.134 on Windows and OS X and before…
CVE-2014-4121 — Critical (CVSS 10.0): Microsoft .NET Framework 2.0 SP2, 3.5, 3.5.1, 4, 4.5, 4.5.1, and 4.5.2 does not properly parse internationalized…
CVE-2014-0560 — Critical (CVSS 10.0): Use-after-free vulnerability in Adobe Reader and Acrobat 10.x before 10.1.12 and 11.x before 11.0.09 on Windows and OS…

Browse all CWE-399 (Resource Management Errors) vulnerabilities →