How severe is CVE-2020-27739?

CVE-2020-27739 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-2020-27739 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-27739?

CVE-2020-27739 affects Citadel Webcit. See the affected-products list for the exact vulnerable versions.

How do I fix CVE-2020-27739?

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-2020-27739 published?

CVE-2020-27739 was published on 2020-10-28 and last updated on 2026-06-17.

CVE-2020-27739

CVE-2020-27739 is a critical-severity vulnerability in Citadel Webcit 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-613.

Key facts

Severity: Critical (CVSS 3.x base score 9.8)
CVSS v2: 7.5
EPSS exploit prediction: 2% (76th percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-613
Affected product: Citadel Webcit
Published: 2020-10-28
Last modified: 2026-06-17

Description

A Weak Session Management vulnerability in Citadel WebCit through 926 allows unauthenticated remote attackers to hijack recently logged-in users' sessions. NOTE: this was reported to the vendor in a publicly archived "Multiple Security Vulnerabilities in WebCit 926" thread.

Frequently asked questions

What is CVE-2020-27739?: A Weak Session Management vulnerability in Citadel WebCit through 926 allows unauthenticated remote attackers to hijack recently logged-in users' sessions. NOTE: this was reported to the vendor in a publicly archived "Multiple Security Vulnerabilities in WebCit 926" thread.
How severe is CVE-2020-27739?: CVE-2020-27739 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-2020-27739 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 2% (76th percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-27739?: CVE-2020-27739 affects Citadel Webcit. See the affected-products list for the exact vulnerable versions.
How do I fix CVE-2020-27739?: 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-2020-27739 published?: CVE-2020-27739 was published on 2020-10-28 and last updated on 2026-06-17.

References

Affected products (1)

cpe:2.3:a:citadel:webcit:*:*:*:*:*:*:*:*

More vulnerabilities in Citadel Webcit

CVE-2009-0364 — High (CVSS 7.5): Format string vulnerability in the mini_calendar component in Citadel.org WebCit 7.22, and other versions before 7.39,…
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CVE-2020-27742 — Medium (CVSS 6.5): An Insecure Direct Object Reference vulnerability in Citadel WebCit through 926 allows authenticated remote attackers…
CVE-2020-27741 — Medium (CVSS 6.1): Multiple cross-site scripting (XSS) vulnerabilities in Citadel WebCit through 926 allow remote attackers to inject…
CVE-2020-29547 — Medium (CVSS 5.9): An issue was discovered in Citadel through webcit-926. Meddler-in-the-middle attackers can pipeline commands after POP3…
CVE-2020-27740 — Medium (CVSS 5.3): Citadel WebCit through 926 allows unauthenticated remote attackers to enumerate valid users within the platform. NOTE:…

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