How severe is CVE-2018-20809?

CVE-2018-20809 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.

Is CVE-2018-20809 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2018-20809?

CVE-2018-20809 primarily affects Ivanti Connect Secure. In total, 96 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2018-20809?

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-2018-20809 published?

CVE-2018-20809 was published on 2019-06-28 and last updated on 2026-06-17.

CVE-2018-20809

CVE-2018-20809 is a high-severity vulnerability in Ivanti Connect Secure with a CVSS 3.x base score of 7.5. 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: High (CVSS 3.x base score 7.5)
CVSS v2: 5.0
EPSS exploit prediction: 3% (84th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-20
Affected product: Ivanti Connect Secure
Published: 2019-06-28
Last modified: 2026-06-17

Description

A crafted message can cause the web server to crash with Pulse Secure Pulse Connect Secure (PCS) 8.3RX before 8.3R5 and Pulse Policy Secure 5.4RX before 5.4R5. This is not applicable to PCS 8.1RX.

Frequently asked questions

What is CVE-2018-20809?: A crafted message can cause the web server to crash with Pulse Secure Pulse Connect Secure (PCS) 8.3RX before 8.3R5 and Pulse Policy Secure 5.4RX before 5.4R5. This is not applicable to PCS 8.1RX.
How severe is CVE-2018-20809?: CVE-2018-20809 has a CVSS 3.x base score of 7.5, rated high severity. It is exploitable over network with low attack complexity, requires no privileges and no user interaction. Impact on confidentiality is none, integrity none, and availability high.
Is CVE-2018-20809 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 3% (84th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2018-20809?: CVE-2018-20809 primarily affects Ivanti Connect Secure. In total, 96 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2018-20809?: 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-2018-20809 published?: CVE-2018-20809 was published on 2019-06-28 and last updated on 2026-06-17.

References

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

Affected products (96)

cpe:2.3:a:ivanti:connect_secure:8.3:r1:*:*:*:*:*:*
cpe:2.3:a:ivanti:connect_secure:8.3:r2:*:*:*:*:*:*
cpe:2.3:a:ivanti:connect_secure:8.3:r2.1:*:*:*:*:*:*
cpe:2.3:a:ivanti:connect_secure:8.3:r3:*:*:*:*:*:*
cpe:2.3:a:ivanti:connect_secure:8.3:r4:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r1.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r1.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r10:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r11.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r12.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r13.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r13.2:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r13.3:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r130:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r2.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r3.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r4.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r5.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r6.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r7.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:4.4:r8.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r1.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r10.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r11.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r12.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r13.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r13.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r2.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r3.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r3.2:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r4.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r4.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r5.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r6.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r7.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r7.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r8.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r8.1:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.0:r9.0:*:*:*:*:*:*
cpe:2.3:a:pulsesecure:pulse_policy_secure:5.1:r1.0:*:*:*:*:*:*

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