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Fencer Vulns
medium 5.9

CVE-2026-45691 json

Nextcloud: Bypass of second factor authentication on DAV endpoints

published 2026-06-01 5 mo ago modified 2026-09-08 2 mo ago also BIT-nextcloud-2026-45691 , EUVD-2026-33718 , GHSA-mp6x-g55j-w9jw

cvss
5.9
version 3.1, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.3%
EPSS 0.3% chance of exploitation in 30 days, percentile 21%
public exploits
0
none known

Summary

Nextcloud is an open source content collaboration platform. In Nextcloud Server from versions 32.0.0 to before 32.0.9, and 33.0.0 to before 33.0.3, a pre-2FA session cookie (created after successful password authentication but before TOTP completion) could be reused as a Bearer token to authenticate against DAV endpoints, granting read/write access and bypassing mandatory two-factor authentication. It is recommended that the Nextcloud Server is upgraded to 33.0.3 or 32.0.9. It is recommended that the Nextcloud Enterprise Server is upgraded to 33.0.3, 32.0.9, 31.0.14.5, 30.0.17.9 or 29.0.16.16

Patch / fix

  • bitnami nextcloud 32.0.9, 33.0.3
  • nextcloud nextcloud 32.0.9, 33.0.3
  • nextcloud nextcloud_server 32.0.9, 33.0.3
  • nextcloud server 32.0.9, 33.0.3

Vendor advisories

What the vendors themselves say about their products: affected, fixed or not affected, and what to do.

red hat product security vex CVE-2026-45691 updated cvss 6.8

nextcloud-server: Nextcloud Server: Two-factor authentication bypass via session cookie reuse

  • Red Hat All currently supported Red Hat products
    not affected: vulnerable code not present

Red Hat CSAF VEX © Red Hat, Inc., from https://security.access.redhat.com/data/csaf/v2/vex/; changed: reduced to product statuses and remediations. CC BY 4.0 · csaf

CISA SSVC

Exploitation
none
Automatable
no
Technical impact
partial
Assessed
5 mo ago

Exploit prediction

0.29% chance of exploitation in the next 30 days, higher than 21% of all scored CVEs (FIRST EPSS, 2026-11-08).

CVSS scores

assigned by version score vector
CNA 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N
OSV 3.1 5.9 CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:H/A:N

Affected packages

ecosystem package affected fixed in
bitnami nextcloud
>=32.0.0, <32.0.9
>=33.0.0, <33.0.3
32.0.9
33.0.3

Affected products

  • nextcloud security-advisories

Classification

Weakness

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.