CVE-2023-45148Network attack vector

Authenticated rate-limit bypass via evictable Memcached counters

Published Oct 16, 2023 · Updated Sep 16, 2024

Rate-limit bypass in Nextcloud Server allows remote authenticated users to exceed configured request limits through affected endpoints. The rate-limiter backend selector stores counters in the configured distributed cache even when it is Memcached, whose entries can disappear before their intended retention period. Exposure requires an affected release configured with Memcached for memcache.distributed; premature counter loss permits repeated requests beyond the intended threshold.

CVSS severity4.3
Medium
EPSS probability0.70%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Rate-limit bypass in Nextcloud Server allows remote authenticated users to exceed configured request limits through affected endpoints. The rate-limiter backend selector stores counters in the configured distributed cache even when it is Memcached, whose entries can disappear before their intended retention period. Exposure requires an affected release configured with Memcached for memcache.distributed; premature counter loss permits repeated requests beyond the intended threshold.

The record

CVE
CVE-2023-45148
Published
Oct 16, 2023
Updated
Sep 16, 2024
Vendor
Nextcloud GmbH
Product
Security Advisories
Classifications
CWE-307
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 16, 2023CVE publishedPublication date reported by the CVE source.
  2. Sep 16, 2024Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=>= 25.0.0, < 25.0.11
  2. Affected versionversion=>= 26.0.0, < 26.0.6
  3. Affected versionversion=>= 27.0.0, < 27.1.0

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

Nextcloud GmbH · Security Advisoriesversion=>= 25.0.0, < 25.0.11; version=>= 26.0.0, < 26.0.6; version=>= 27.0.0, < 27.1.0

Published CVSS scores

4.3NIST NVDCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L
4.3NextcloudCVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-307Improper Restriction of Excessive Authentication Attempts

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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