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Vulnerabilities

Vulnerability · CVE-2020-36851

Rob--W cors-anywhere instances configured as an open proxy allow unauthenticated external users to induce the server to make HTTP requests to arbitrary targets (SSRF).

Published Sep 25, 2025 · catalog updated Oct 8, 2026 · Rob--W / cors-anywhere Rob--W / cors-anywhere

Last checked Oct 23, 2026. A connected source was read within the last 7 days.

Check if you run it

No confirmed exploitation is on record for CVE-2020-36851. EPSS is 0.83%. Act only if a listed version of Rob--W / cors-anywhere Rob--W / cors-anywhere is installed.

Gaps on this record

  • No vendor fix or required action is stored. Compare the linked advisory before you change production.
Severity
Critical9.5
Known exploitation
Not in CISA/VulnCheck KEV
EPSS
0.83%
Remediation
Advisory link
Affected products
vendor Rob--W / cors-anywhere Rob--W / cors-anywhere 0 ≤0.4.4

Rob--W cors-anywhere instances configured as an open proxy allow unauthenticated external users to induce the server to make HTTP requests to arbitrary targets (SSRF). Because the proxy forwards requests and headers, an attacker can reach internal-only endpoints and link-local metadata services, retrieve instance role credentials or other sensitive metadata, and interact with internal APIs and services that are not intended to be internet-facing. The vulnerability is exploitable by sending crafted requests to the proxy with the target resource encoded in the URL; many cors-anywhere deployments

Are you affected?

Enter the version you run. The result uses only the ranges stored on this record.

The check returns affected, not affected, or incomplete. It does not guess a version that is missing from the record.

  • vendor Rob--W / cors-anywhere Rob--W / cors-anywhere 0 ≤0.4.40 ≤0.4.4

How to fix CVE-2020-36851

What to do

Three questions, each answered from this record only. Confirm the vendor advisory before you patch.

Should you patch?

No confirmed exploitation is on record for CVE-2020-36851. EPSS is 0.83%. Act only if a listed version of Rob--W / cors-anywhere Rob--W / cors-anywhere is installed.

Which versions are affected?

Compare what you have installed with Rob--W / cors-anywhere Rob--W / cors-anywhere 0 ≤0.4.4 0 ≤0.4.4. Compare the installed version with the linked vendor advisory before you change production.

What should an analyst verify?

No weakness class is stored. EPSS 0.83%. There is no CISA KEV listing. No Exploit-DB or Metasploit reference is linked. Use the source links for the original advisory.

Code

The project this record applies to. Exploit listings stay in References.

Timeline

Detection, updates, and resolution for this record.

  1. Sep 25, 2025 · EUVD

    Detected

    Rob--W cors-anywhere instances configured as an open proxy allow unauthenticated external users to induce the server to make HTTP requests to arbitrary targets (SSRF). Because the proxy forwards requests and headers, an attacker can reach internal-only endpoints and link-local metadata services, retrieve instance role credentials or other sensitive metadata, and interact with internal APIs and ser

  2. Oct 8, 2026 · EUVD

    Updated

    Rob--W cors-anywhere instances configured as an open proxy allow unauthenticated external users to induce the server to make HTTP requests to arbitrary targets (SSRF). Because the proxy forwards requests and headers, an attacker can reach internal-only endpoints and link-local metadata services, retrieve instance role credentials or other sensitive metadata, and interact with internal APIs and ser

Sources

  • CVE.orgVulnerability recordCVE-2020-36851

    Official CVE identifier

    cve.org
  • FIRST EPSSExploitation probabilityCVE-2020-36851

    30-day exploitation probability 0.83%

    first.org
  • EUVDVulnerability recordEUVD-2020-30801

    Rob--W cors-anywhere instances configured as an open proxy allow unauthenticated external users to induce the server to make HTTP requests to arbitrary targets (SSRF). Because the proxy forwards requests and headers, an attacker can reach internal-only endpoints and link-local me

    euvd.enisa.europa.eu

References

Freshness

Last verified in this catalog Oct 23, 2026. Significant claims (KEV, EPSS, CVSS, affected ranges) come from the source rows above — open the original publisher for the authoritative advisory.

  • FIRST EPSSOct 23, 2026
  • CVE.orgOct 22, 2026
  • EUVDOct 22, 2026