How severe is CVE-2020-25864?

CVE-2020-25864 has a CVSS score of 6.1/10, rated MEDIUM. Review your exposure and patch according to your risk tolerance.

Which packages are affected by CVE-2020-25864?

CVE-2020-25864 affects the following packages: github.com/hashicorp/consul (Go), github.com/hashicorp/consul (Go), github.com/hashicorp/consul (Go). Ecosystems affected: Go.

How do I fix CVE-2020-25864?

Update github.com/hashicorp/consul to 1.9.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-25864 is resolved across your whole dependency graph.

How do I detect CVE-2020-25864 in my Go dependencies?

Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/hashicorp/consul, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.

How do I mitigate CVE-2020-25864 if there is no patch (or I can't update yet)?

Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

Is CVE-2020-25864 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-25864 yet. This does not mean the vulnerability cannot be exploited — absence of public exploits does not imply safety. Apply the recommended fix and use O3 Security to monitor your exposure.

What is the EPSS score for CVE-2020-25864?

CVE-2020-25864 has an EPSS (Exploit Prediction Scoring System) score of 6.1%, placing it in the 93th percentile of all CVEs. EPSS is maintained by FIRST.org and estimates the probability that a vulnerability will be exploited in the wild within the next 30 days. This score indicates relatively lower exploitation probability, though the CVSS severity should still guide your patching priority.

What type of vulnerability is CVE-2020-25864?

CVE-2020-25864 is classified as Cross-site Scripting (XSS) (CWE-79). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation. This is a high-impact weakness class that often enables remote code execution or data exposure.

Is there exploit tooling available for CVE-2020-25864?

A Nuclei detection template exists for CVE-2020-25864, meaning automated scanners can fingerprint it. Public exploit tooling significantly increases real-world risk — prioritize patching and ensure detection coverage. Exploit tooling should only ever be used in isolated, authorized testing environments.

When was CVE-2020-25864 published, and has it been updated?

CVE-2020-25864 was published on April 20, 2021 and was last updated on October 24, 2026. Advisory data evolves as severity scores, affected ranges, and exploit intelligence are revised — always check the latest version of the advisory before acting.

🐹

🐹 Go

Not in CISA KEV

MEDIUM severity

CVE-2020-25864 — consul

MEDIUM

CVE-2020-25864 is a medium-severity (CVSS 6.1) Cross-site Scripting (XSS) vulnerability in github.com/hashicorp/consul. A fix is available for github.com/hashicorp/consul — see the affected versions and patch details below.

HashiCorp Consul Cross-site Scripting vulnerability

Also known asBIT-consul-2020-25864GHSA-8xmx-h8rq-h94jGO-2023-1851

Published

Apr 20, 2021

Updated

Oct 24, 2026

Affected

3 pkgs

Patched

3 / 3

Exploits

None indexed

Exploitation data as of Oct 27, 2026 · OSV.dev, NVD, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

6.1%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs93th percentile — riskier than 93% of all scored CVEsHighest risk

Probability of exploitation in the next 30 days, from FIRST.org EPSS.

How urgent is this, really

Where this sits among everything scored

Real-World Exposure

3 pkgs affected

🐹github.com/hashicorp/consul🐹github.com/hashicorp/consul🐹github.com/hashicorp/consul

Real-time download stats are indexed for npm and PyPI packages. This vulnerability affects Go packages — download data is not available via public APIs for these ecosystems.

Description

HashiCorp Consul and Consul Enterprise up to version 1.9.4 key-value (KV) raw mode was vulnerable to cross-site scripting. Fixed in 1.9.5, 1.8.10 and 1.7.14.

Affected Packages

3 total 3 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/hashicorp/consul`	≥ 1.9.0&&< 1.9.5	1.9.5`go get github.com/hashicorp/consul@v1.9.5`
🐹Go	`github.com/hashicorp/consul`	≥ 1.8.0&&< 1.8.10	1.8.10`go get github.com/hashicorp/consul@v1.8.10`
🐹Go	`github.com/hashicorp/consul`	all versions	1.7.14`go get github.com/hashicorp/consul@v1.7.14`

Affected Products

1 product · 6 configurations

Application

consulhashicorp

≥ 1.9.0 && < 1.9.5

range

Detection & mitigation playbook

Open-source dependency

Detect
Scan your dependency tree (package-lock.json, pnpm-lock.yaml, requirements.txt, go.sum, etc.) for github.com/hashicorp/consul, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/hashicorp/consul to 1.9.5 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-25864 is resolved across your whole dependency graph.
Workarounds
Escape or sanitise the affected output on the server side rather than relying on client-side filtering, and add a Content-Security-Policy that blocks inline script execution so injected markup cannot run even if it reaches the page.

How to detect CVE-2020-25864

A community-maintained Nuclei template exists for this CVE. You can scan for it directly:

nuclei -id cve-2020-25864 -u https://target

Template: HashiCorp Consul/Consul Enterprise <=1.9.4 - Cross-Site Scripting
Severity: medium
Impact: Successful exploitation of this vulnerability could allow an attacker to execute arbitrary JavaScript code in the context of the victim's browser, leading to potential data theft, session hijacking, or defacement of the affected Consul/Consul Enterprise application.
Remediation: Fixed in 1.9.5, 1.8.10 and 1.7.14.

Template by ProjectDiscovery nuclei-templates (c-sh0), MIT licensed. View the full template. Scan only systems you are authorised to test.

Frequently Asked Questions

HashiCorp Consul and Consul Enterprise up to version 1.9.4 key-value (KV) raw mode was vulnerable to cross-site scripting. Fixed in 1.9.5, 1.8.10 and 1.7.14.

O3 Security · Impact-Aware SCA

Is CVE-2020-25864 in your dependencies?

Find it across Go, including transitive dependencies.

Scan my dependencies How O3 SCA works

CVSS Score

6.1/10CVSS v3 base

Vector breakdown

Attack Vector

Network

Attack Complexity

Low

Privileges Required

None

User Interaction

Required

Scope

Changed

Confidentiality

Low

Integrity

Low

Availability

None

Raw vector

CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N

CWE Classification

CWE-79Cross-site Scripting (XSS)

Weaponization

OpenSSF Scorecard

Package health score

consul

7.9/10

Maintained10/10

Code-Review10/10

Branch-Protection8/10

Assessed Oct 26, 2026

Timeline

Disclosed

Apr 20, 2021

Last updated

Oct 24, 2026

Identifiers

CVE-2020-25864

GHSA-8xmx-h8rq-h94j

BIT-consul-2020-25864

GO-2023-1851

References

Advisorydiscuss.hashicorp.com Advisorysecurity.gentoo.org · 202208 09 Advisoryhashicorp.com · consul Advisorynvd.nist.gov · CVE 2020 25864 Packagegithub.com · consul

Related vulnerabilities

This CVE is medium severity; 8 of 8 other CVEs affecting consul are rated as high or higher (top: high).

CVE-2026-2808CVE-2025-11374CVE-2025-11375CVE-2024-10006CVE-2024-10086CVE-2024-10005CVE-2020-25201CVE-2020-28053

Provenance

Sources

OSV.devNVDFIRST.org (EPSS)

Last verifiedOct 24, 2026