What’s Vulnerable › Vulnerabilities

CVE-2021-32741: Lack of ratelimit on public share link mount endpoint

• Severity: medium (CVSS 5.3 v3.1)
• Exploited in the wild: not listed in CISA KEV
• EPSS: 1.3% probability of exploitation in the next 30 days
• Public exploit or detection template: none known
• Published: 2021-07-12 · updated 2026-06-17
• Weakness: CWE-799

Description

Nextcloud Server is a Nextcloud package that handles data storage. In versions prior to 19.0.13, 20.011, and 21.0.3, there was a lack of ratelimiting on the public share link mount endpoint. This may have allowed an attacker to enumerate potentially valid share tokens. The issue was fixed in versions 19.0.13, 20.0.11, and 21.0.3. There are no known workarounds.

Affected products

• Nextcloud Server: before 19.0.13; from 20.0.0 before 20.0.11; from 21.0.0 before 21.0.3 — fixed in 19.0.13, 20.0.11, 21.0.3

How to fix

Upgrade to a fixed version: Nextcloud Server 19.0.13, 20.0.11, 21.0.3. Check the vendor advisory for mitigations.

References

• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-crvj-vmf7-xrvr
• https://github.com/nextcloud/server/pull/26958
• https://hackerone.com/reports/1192144
• https://github.com/nextcloud/security-advisories/security/advisories/GHSA-crvj-vmf7-xrvr
• https://github.com/nextcloud/server/pull/26958
• https://hackerone.com/reports/1192144

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