Nextcloud: PIN bypass in PassCodeActivity via back button

published 2026-06-01 5 mo ago modified 2026-07-22 3 mo ago also BIT-nextcloud-2026-45153 , EUVD-2026-33672 , GHSA-2w7v-5299-3hw5

cvss: 4.6; version 3.1, CNA
cisa kev: Not listed; not in CISA's catalog
epss: 0.2%; EPSS 0.2% chance of exploitation in 30 days, percentile 4%
public exploits: 0; none known

Nextcloud is an open source content collaboration platform. From version 33.0.0 to before version 33.1.0, after unlocking a locked Android phone the back-button could be used to bypass the Nextcloud Files app PIN. This issue has been patched in version 33.1.0.

Patch / fix

fixed in 2 links 1

bitnami nextcloud 33.1.0
nextcloud nextcloud 33.1.0

github.com/nextcloud/android#16896 pull request

CISA SSVC

Exploitation: none
Automatable: no
Technical impact: partial
Assessed: 5 mo ago (2026-06-01)

Exploit prediction

0.15% chance of exploitation in the next 30 days, higher than 4% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by	version	score	vector
CNA	3.1	4.6	CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N
OSV	3.1	4.6	CVSS:3.1/AV:P/AC:H/PR:L/UI:N/S:U/C:H/I:L/A:N

Affected packages

ecosystem	package	affected	fixed in
bitnami	nextcloud	>=33.0.0, <33.1.0	33.1.0

Affected products

nextcloud security-advisories

Classification

Weakness

CWE-287 Improper Authentication

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.

Summary