Pi-hole 5.0, 5.1, and 5.1.1 allows Session Fixation.

published 2021-02-18 5y ago modified 2026-06-17 4mo ago also EUVD-2020-23257

cvss: 5.4; version 3.1, NVD
cisa kev: Not listed; not in CISA's catalog
epss: 1.1%; EPSS 1.1% chance of exploitation in 30 days, percentile 66%
public exploits: 0; none known

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.

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Exploit prediction

1.14% chance of exploitation in the next 30 days, higher than 66% of all scored CVEs (FIRST EPSS, 2026-11-09).

Exploits and checks

n4nj0.github.io https://n4nj0.github.io/advisories/pi-hole-multiple-vulnerabilities-i/ referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by	version	score	vector
NVD	3.1	5.4	CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:L/I:L/A:N
NVD	2.0	5.8	AV:N/AC:M/Au:N/C:P/I:P/A:N

Classification

Weakness

CWE-384 Session Fixation

References

n4nj0.github.io /advisories/pi-hole-multiple-vulnerabilities-i/
exploit, third-party-advisory
discourse.pi-hole.net /c/announcements/5
release-notes, vendor-advisory

Sources

CVE List CVE-2020-35591
NVD CVE-2020-35591

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