How severe is CVE-2018-6320?

CVE-2018-6320 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.

Is CVE-2018-6320 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-6320?

CVE-2018-6320 primarily affects Ivanti Connect Secure. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-6320?

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-2018-6320 published?

CVE-2018-6320 was published on 2018-09-06 and last updated on 2026-06-17.

CVE-2018-6320

CVE-2018-6320 is a critical-severity vulnerability in Ivanti Connect Secure with a CVSS 3.x base score of 9.8. 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-20.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 4% (89th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Ivanti Connect Secure
Published: 2018-09-06
Last modified: 2026-06-17

Description

A vulnerability has been discovered in login.cgi in Pulse Secure Pulse Connect Secure (PCS) 8.1RX before 8.1R12 and 8.3RX before 8.3R2 and Pulse Policy Secure (PPS) 5.2RX before 5.2R9 and 5.4RX before 5.4R2 wherein an http(s) Host header received from the browser is trusted without validation.

Frequently asked questions

What is CVE-2018-6320?: A vulnerability has been discovered in login.cgi in Pulse Secure Pulse Connect Secure (PCS) 8.1RX before 8.1R12 and 8.3RX before 8.3R2 and Pulse Policy Secure (PPS) 5.2RX before 5.2R9 and 5.4RX before 5.4R2 wherein an http(s) Host header received from the browser is trusted without validation.
How severe is CVE-2018-6320?: CVE-2018-6320 has a CVSS 3.x base score of 9.8, rated critical severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is high, integrity high, and availability high.
Is CVE-2018-6320 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 4% (89th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-6320?: CVE-2018-6320 primarily affects Ivanti Connect Secure. In total, 18 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-6320?: 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-2018-6320 published?: CVE-2018-6320 was published on 2018-09-06 and last updated on 2026-06-17.

References

https://kb.pulsesecure.net/articles/Pulse_Security_Advisories/SA43877

Affected products (18)

cpe:2.3:a:ivanti:connect_secure:8.1:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_connect_secure:8.1r1.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_connect_secure:8.1rx:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_connect_secure:8.3rx:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r1.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r2.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r3.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r3.2:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r4.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r5.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r6.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r7.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r7.1:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2r8.0:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.2rx:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.4r1:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.4r2:*:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.4rx:*:*:*:*:*:*:*

More vulnerabilities in Ivanti Connect Secure

CVE-2021-22893 — Critical (CVSS 10.0): Pulse Connect Secure 9.0R3/9.1R1 and higher is vulnerable to an authentication bypass vulnerability exposed by the…
CVE-2019-11510 — Critical (CVSS 10.0): In Pulse Secure Pulse Connect Secure (PCS) 8.2 before 8.2R12.1, 8.3 before 8.3R7.1, and 9.0 before 9.0R3.4, an…
CVE-2016-4787 — Critical (CVSS 10.0): Pulse Connect Secure (PCS) 8.2 before 8.2r1, 8.1 before 8.1r2, 8.0 before 8.0r10, and 7.4 before 7.4r13.4 allow remote…
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CVE-2024-21894 — Critical (CVSS 9.8): A heap overflow vulnerability in IPSec component of Ivanti Connect Secure (9.x, 22.x) and Ivanti Policy Secure allows…
CVE-2018-20813 — Critical (CVSS 9.8): An input validation issue has been found with login_meeting.cgi in Pulse Secure Pulse Connect Secure 8.3RX before 8.3R2.

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