CVE-2020-36474Network attack vector

Server-side request forgery via unpinned DNS

Published Aug 20, 2021 · Updated Aug 4, 2024

DNS rebinding in Vanilla SafeCurl before 0.9.2 allows remote attackers to make cURL connect to a different IP after URL validation. SafeCurl.execute checks a hostname against an IP blacklist but does not pin the validated address when cURL resolves the hostname for the request. Exploitation requires an application to pass an attacker-controlled URL to the library, enabling requests to an address that the initial check would reject.

CVSS severity9.8
Critical
EPSS probability1.80%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

DNS rebinding in Vanilla SafeCurl before 0.9.2 allows remote attackers to make cURL connect to a different IP after URL validation. SafeCurl.execute checks a hostname against an IP blacklist but does not pin the validated address when cURL resolves the hostname for the request. Exploitation requires an application to pass an attacker-controlled URL to the library, enabling requests to an address that the initial check would reject.

The record

CVE
CVE-2020-36474
Published
Aug 20, 2021
Updated
Aug 4, 2024
Vendor
Unknown vendor
Product
Unknown product
Classifications
Unavailable
Attack vector
network
Privileges
unauthenticated

Timeline

How it unfolded

  1. Aug 20, 2021CVE publishedPublication date reported by the CVE source.
  2. Aug 4, 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?

Affected buildAffected product and version details are unavailable.

What conditions does exploitation require?

Attack vectornetwork
Required privilegesunauthenticated

What is affected?

Affected products and versions are unavailable in this record.

Published CVSS scores

7.5NIST NVDAV:N/AC:L/Au:N/C:P/I:P/A:P
9.8NIST NVDCVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H

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
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

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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