How severe is CVE-2020-24356?

CVE-2020-24356 has a CVSS score of 7.8/10, rated HIGH. Immediate patching is strongly recommended.

Which packages are affected by CVE-2020-24356?

CVE-2020-24356 affects the following packages: github.com/cloudflare/cloudflared (Go). Ecosystems affected: Go.

How do I fix CVE-2020-24356?

Update github.com/cloudflare/cloudflared to 0.0.0-20200820025921-9323844ea773 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-24356 is resolved across your whole dependency graph.

How do I detect CVE-2020-24356 in my Go dependencies?

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

How do I mitigate CVE-2020-24356 if there is no patch (or I can't update yet)?

If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.

How does O3 Security protect against CVE-2020-24356?

O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2020-24356 can be triaged on real exposure rather than presence alone.

Is CVE-2020-24356 actively exploited in the wild?

No public exploit code has been indexed for CVE-2020-24356 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-2020-24356?

CVE-2020-24356 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 26th 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.

When was CVE-2020-24356 published, and has it been updated?

CVE-2020-24356 was published on October 2, 2020 and was last updated on July 9, 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

HIGH severity

CVE-2020-24356 — cloudflared

HIGHFix: cloudflare/cloudflared@9323844

CVE-2020-24356 is a high-severity (CVSS 7.8) vulnerability in github.com/cloudflare/cloudflared. A fix is available for github.com/cloudflare/cloudflared — see the affected versions and patch details below.

Local Privilege Escalation in cloudflared

Also known asGHSA-hgwp-4vp4-qmm2GO-2022-0845

Published

Oct 2, 2020

Updated

Jul 9, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

Exploitation data as of Sep 24, 2026 · OSV.dev, FIRST.org (EPSS)

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs26th percentile — riskier than 26% of all scored CVEsHighest risk

EPSS (Exploit Prediction Scoring System) is a daily probability model maintained by FIRST.org. It estimates the likelihood a CVE will be exploited in production environments within the next 30 days, derived from real-world threat intelligence signals.

How urgent is this, really

CVE-2020-24356 plotted by exploitation likelihood (EPSS) against impact (CVSS). The shaded corner — EPSS 50%+ and CVSS 7.0+ — is where this CVE doesn't sit, though severity or exploitability alone can still warrant action.

Where this sits among everything scored

Of 378,156 CVEs with a current EPSS score, this one falls in the < 10% band (highlighted). Real counts from FIRST.org, not a sample — log-scaled since the landscape is heavily right-skewed.

Real-World Exposure

1 pkg affected

🐹github.com/cloudflare/cloudflared

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

In cloudflared versions < 2020.8.1 (corresponding to 0.0.0-20200820025921-9323844ea773 on pkg.go.dev) on Windows, if an administrator has started cloudflared and set it to read configuration files from a certain directory, an unprivileged user can exploit a misconfiguration in order to escalate privileges and execute system-level commands. The misconfiguration was due to the way that cloudflared reads its configuration file. One of the locations that cloudflared reads from (C:\etc) is not a secure by default directory due to the fact that Windows does not enforce access controls on this directory without further controls applied. A malformed config.yaml file can be written by any user. Upon reading this config, cloudflared would output an error message to a log file defined in the malformed config. The user-controlled log file location could be set to a specific location that Windows will execute when any user logs in.

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/cloudflare/cloudflared`	all versions	0.0.0-20200820025921-9323844ea773`go get github.com/cloudflare/cloudflared@v0.0.0-20200820025921-9323844ea773`

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/cloudflare/cloudflared, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/cloudflare/cloudflared to 0.0.0-20200820025921-9323844ea773 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2020-24356 is resolved across your whole dependency graph.
Workarounds
If you can't upgrade right away: gate or disable the affected feature, validate untrusted input at the boundary, and avoid passing attacker-controlled data into the vulnerable path. O3's runtime protection blocks exploitation in production as an interim safeguard until the upgrade lands.
How O3 protects you
O3 Security's impact-aware SCA analyses which vulnerable code paths your application actually calls, so a match like CVE-2020-24356 can be triaged on real exposure rather than presence alone.

Tailored to CVE-2020-24356. Runtime protection reduces exposure until a permanent patch is applied and verified — it complements patching, it doesn't replace it.

Frequently Asked Questions

In `cloudflared` versions < 2020.8.1 (corresponding to 0.0.0-20200820025921-9323844ea773 on pkg.go.dev) on Windows, if an administrator has started `cloudflared` and set it to read configuration files from a certain directory, an unprivileged user can exploit a misconfiguration in order to escalate privileges and execute system-level commands. The misconfiguration was due to the way that `cloudflared` reads its configuration file. One of the locations that `cloudflared` reads from (C:\etc\) is not a secure by default directory due to the fact that Windows does not enforce access controls on th

O3 Security · Impact-Aware SCA

Is CVE-2020-24356 in your dependencies?

O3 Security finds CVE-2020-24356 across Go dependencies, including transitive ones, and its impact-aware SCA ranks findings by whether your code actually calls the vulnerable path.

Scan my dependencies How O3 SCA works