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Public proof of conceptFix available

CVE-2020-35590

A public proof of concept exists; no exploitation attested.

  • Published2020-12-21
  • Fixed in2.17.4
  • WeaknessCWE-307

Am I affected?

With a domain, we read the version its public headers and pages expose. A distribution build can carry the fix under an older number.

Description

LimitLoginAttempts.php in the limit-login-attempts-reloaded plugin before 2.17.4 for WordPress allows a bypass of (per IP address) rate limits because the X-Forwarded-For header can be forged. When the plugin is configured to accept an arbitrary header for the client source IP address, a malicious user is not limited to perform a brute force attack, because the client IP header accepts any arbitrary string. When randomizing the header input, the login count does not ever reach the maximum allowed retries.

Timeline

dates in UTC
  1. 2020-12-2107:15CVE publishedNVD
  2. 2026-10-2319:23First public proof of conceptPoC-in-GitHub

Observed activity

isMalicious corpus · updated 2026-10-23 18:48 UTC
Indicators tagged with this CVE, per day0 indicators over 7 days
Block these indicators
  • Firewall list (EDL, text): https://api.ismalicious.com/edl/cve/CVE-2020-35590?format=txt
  • CSV export: https://api.ismalicious.com/edl/cve/CVE-2020-35590?format=csv
  • TAXII collection of exploited CVEs
  • The EDL and CSV take an API key on the Pro plan.

Versions per branch

NVD
Limitloginattempts limit login attempts reloaded
BranchAffectedFixed in
2.17< 2.17.42.17.4

as publishedRanges as NVD and OSV publish them; a distribution’s build can be fixed under an older number.

Fix

  1. Update Limitloginattempts limit login attempts reloaded to 2.17.4

Detection

read 2026-10-23 19:23 UTC
Nuclei template
none so far
ProjectDiscovery
Exploit-DB
no entry
Exploit-DB
Proof-of-concept repositories
1 repository, unverifiedN4nj0/CVE-2020-35590
PoC-in-GitHub

Sources

  • NVDCVSS 3.19.8read 2026-10-23
  • NVDCVSS 2.05read 2026-10-23
  • NVDweakness (CWE)CWE-307read 2026-10-23
  • FIRST EPSSEPSS score4.3 %2026-10-22
  • PoC-in-GitHubproof of concept1read 2026-10-23

Technical details

CVSS v3 Vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
Published
2020-12-21
Last Modified
2026-06-17
NVD status
Modified

Frequently asked questions

What is CVE-2020-35590?

LimitLoginAttempts.php in the limit-login-attempts-reloaded plugin before 2.17.4 for WordPress allows a bypass of (per IP address) rate limits because the X-Forwarded-For header can be forged. When the plugin is configured to accept an arbitrary header for the client source IP address, a malicious user is not limited to perform a brute force attack, because the client IP header accepts any arbitrary string. When randomizing the header input, the login count does not ever reach the maximum allowed retries.

Is CVE-2020-35590 actively exploited?

Active exploitation of CVE-2020-35590 has not been confirmed. Its EPSS score was 4.3% on 2026-10-22, the estimated probability of exploitation in the next 30 days.

What is the CVSS score for CVE-2020-35590?

CVE-2020-35590 has a CVSS v3 base score of 9.8 (CRITICAL severity), with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.

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