How severe is CVE-2020-35591?

CVE-2020-35591 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.

Is CVE-2020-35591 being actively exploited?

It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.

What products are affected by CVE-2020-35591?

CVE-2020-35591 primarily affects Pi-hole. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.

How do I fix CVE-2020-35591?

Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.

When was CVE-2020-35591 published?

CVE-2020-35591 was published on 2021-02-18 and last updated on 2026-06-17.

CVE-2020-35591

CVE-2020-35591 is a medium-severity vulnerability in Pi-hole with a CVSS 3.x base score of 5.4. 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-384.

Key facts

Severity: Medium (CVSS 3.x base score 5.4)
CVSS v2: 5.8
EPSS exploit prediction: 1% (63rd percentile)
Actively exploited: Not listed in CISA KEV
Weakness: CWE-384
Affected product: Pi-hole
Published: 2021-02-18
Last modified: 2026-06-17

Description

Pi-hole 5.0, 5.1, and 5.1.1 allows Session Fixation. The application does not generate a new session cookie after the user is logged in. A malicious user is able to create a new session cookie value and inject it to a victim. After the victim logs in, the injected cookie becomes valid, giving the attacker access to the user's account through the active session.

Frequently asked questions

What is CVE-2020-35591?: Pi-hole 5.0, 5.1, and 5.1.1 allows Session Fixation. The application does not generate a new session cookie after the user is logged in. A malicious user is able to create a new session cookie value and inject it to a victim. After the victim logs in, the injected cookie becomes valid, giving the attacker access to the user's account through the active session.
How severe is CVE-2020-35591?: CVE-2020-35591 has a CVSS 3.x base score of 5.4, rated medium severity. It is exploitable over network with low attack complexity, requires no privileges and user interaction. Impact on confidentiality is low, integrity low, and availability none.
Is CVE-2020-35591 being actively exploited?: It is not currently listed in CISA's KEV catalog. Its EPSS exploit-prediction score is 1% (63rd percentile), an estimate of the probability of exploitation in the next 30 days.
What products are affected by CVE-2020-35591?: CVE-2020-35591 primarily affects Pi-hole. In total, 3 product configurations (CPEs) are listed as vulnerable; see the affected-products list for the exact versions.
How do I fix CVE-2020-35591?: Review the linked vendor and NVD advisories for patched versions and mitigations, then upgrade or apply the recommended workaround.
When was CVE-2020-35591 published?: CVE-2020-35591 was published on 2021-02-18 and last updated on 2026-06-17.

References

Affected products (3)

cpe:2.3:a:pi-hole:pi-hole:5.0:*:*:*:*:*:*:*
cpe:2.3:a:pi-hole:pi-hole:5.1:*:*:*:*:*:*:*
cpe:2.3:a:pi-hole:pi-hole:5.1.1:*:*:*:*:*:*:*

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