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Fencer Intel
high 7.5

CVE-2026-77167 json

Abusing the federated share endpoint, an attacker can write arbitrary rows into the oc_share_external database table.

published 15d ago modified 7d ago also EUVD-2026-111127

cvss
7.5
version 3.0, CNA
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 30%
public exploits
0
none known

Summary

Abusing the federated share endpoint, an attacker can write arbitrary rows into the oc_share_external database table. These rows persist indefinitely — there is no automatic cleanup mechanism. Three distinct denial-of-service conditions follow from this write primitive, all triggered from the same unauthenticated source and all self-renewing on a 24-hour cycle for as long as the injected rows remain in the database.

Patch / fix

  • nextcloud server 22.2.11, 23.0.13, 24.0.13, 25.0.14, 26.0.14, 27.1.12, 28.0.15, 29.0.17, 30.0.18, 31.0.15, 32.0.13, 33.0.7, 34.0.2
  • nextcloud nextcloud_server 22.2.11, 23.0.13, 24.0.13, 25.0.14, 26.0.14, 27.1.12, 28.0.15, 29.0.17, 30.0.18, 31.0.15, 32.0.13, 33.0.7, 34.0.2
  • nextcloud nextcloud 22.2.11, 23.0.13, 24.0.13, 25.0.14, 26.0.14, 27.1.12, 28.0.15, 29.0.17, 30.0.18, 31.0.15, 32.0.13, 33.0.7, 34.0.2

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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-2026-77167 updated cvss 7.5

nextcloud: Nextcloud: Denial of Service via federated share endpoint abuse

  • 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
yes
Technical impact
partial
Assessed
7d ago

Exploit prediction

0.37% chance of exploitation in the next 30 days, higher than 30% of all scored CVEs (FIRST EPSS, 2026-11-11).

CVSS scores

assigned by version score vector
CNA 3.0 7.5 CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Affected products

  • Nextcloud server

Classification

Weakness
  • CWE-400 Uncontrolled Resource Consumption

References

Sources

Fencer Intel 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.