How severe is CVE-2026-55252?

No CVSS score has been assigned to CVE-2026-55252 yet. Review the advisory details and affected package list to assess your exposure.

Which packages are affected by CVE-2026-55252?

CVE-2026-55252 affects the following packages: github.com/openrundev/openrun (Go). Ecosystems affected: Go.

How do I fix CVE-2026-55252?

Update github.com/openrundev/openrun to 0.17.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55252 is resolved across your whole dependency graph.

How do I detect CVE-2026-55252 in my Go dependencies?

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

How do I mitigate CVE-2026-55252 if there is no patch (or I can't update yet)?

Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Is CVE-2026-55252 actively exploited in the wild?

No public exploit code has been indexed for CVE-2026-55252 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-2026-55252?

CVE-2026-55252 has an EPSS (Exploit Prediction Scoring System) score of 0.3%, placing it in the 24th 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-2026-55252?

CVE-2026-55252 is classified as Open Redirect (CWE-601). This weakness type describe the underlying flaw category, which helps determine the potential impact and the right class of mitigation.

When was CVE-2026-55252 published, and has it been updated?

CVE-2026-55252 was published on October 1, 2026 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

CVE-2026-55252 — openrun

Fix: openrundev/openrun@709da78

CVE-2026-55252 is a Open Redirect vulnerability in github.com/openrundev/openrun. A fix is available for github.com/openrundev/openrun — see the affected versions and patch details below.

OpenRun: Redirect URL validation bypass using //host paths leads to Open Redirect

Also known asGHSA-h5g6-xmh4-hc37GO-2026-5956

Published

Oct 1, 2026

Updated

Oct 24, 2026

Affected

1 pkg

Patched

1 / 1

Exploits

None indexed

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

Exploitation Status

Proof-of-concept exploit code exists

CISA’s SSVC triage found public proof-of-concept exploit code for this CVE, though no confirmed active exploitation.

Exploitation and automatability from CISA’s SSVC triage for CVE-2026-55252.

EPSS Exploitation Probability

via FIRST.org ↗

0.3%probability of exploitation in next 30 days

Lower Risk0.00%

Lower risk than most CVEs24th percentile — riskier than 24% of all scored CVEsHighest risk

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

Real-World Exposure

1 pkg affected

🐹github.com/openrundev/openrun

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

Summary

The restrictions on redirect URLs in openrun can be bypassed by attackers, leading to open redirect attacks.

Details

In the current project, the referrer header value is used for subsequent redirects, so there is currently a validation for this redirect value. The current validation logic requires that the host and schema of the redirect URL be the same as the current website's URL, and finally, the path part is used for redirection. This check seems robust, but it can still be bypassed by attackers.

Here's the problem: Assuming the current website is http://127.0.0.1:25222/, if the attacker passes in a redirect URL of http://127.0.0.1:25222//fushuling.com, its host and schema are obviously the same as the current website, thus bypassing the verification. However, the issue lies in the final redirect URL, which is the path part of the URL, i.e., //fushuling.com.

Browsers automatically complete the HTTP header for URLs starting with //, ultimately successfully bypassing the restriction and redirecting to the external address http://fushuling.com.

This vulnerable behavior was successfully reproduced locally. Normally, specifying an external address directly will be blocked, so it will not redirect.

However, if the redirect URL is http://127.0.0.1:25222//fushuling.com, the existing validation logic is bypassed, and the Location header is successfully set to //fushuling.com.

POST /redirecttest/abc/frag HTTP/1.1
Host: 127.0.0.1:25222
Referer: http://127.0.0.1:25222//fushuling.com
Cache-Control: max-age=0
sec-ch-ua: "Not(A:Brand";v="24", "Chromium";v="122"
sec-ch-ua-mobile: ?0
sec-ch-ua-platform: "Windows"
Upgrade-Insecure-Requests: 1
User-Agent: Mozilla/5.0 (Windows NT 10.0; Win64; x64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/122.0.6261.57 Safari/537.36
Accept: text/html,application/xhtml+xml,application/xml;q=0.9,image/avif,image/webp,image/apng,*/*;q=0.8,application/signed-exchange;v=b3;q=0.7
Sec-Fetch-Site: none
Sec-Fetch-Mode: navigate
Sec-Fetch-User: ?1
Sec-Fetch-Dest: document
Accept-Encoding: gzip, deflate, br
Accept-Language: zh-CN,zh;q=0.9
Connection: close
Content-Type: application/x-www-form-urlencoded
Content-Length: 0

The user was then successfully redirected to the external address http://fushuling.com.

PoC

http://127.0.0.1:25222//fushuling.com

Impact

Open Redirect

Affected Packages

1 total 1 fixed

Ecosystem	Package	Vulnerable range	Fix
🐹Go	`github.com/openrundev/openrun`	all versions	0.17.7`go get github.com/openrundev/openrun@v0.17.7`

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/openrundev/openrun, including transitive dependencies — a direct dependency you never call can still pull in a vulnerable version.
Fix
Update github.com/openrundev/openrun to 0.17.7 or later, then make sure no transitive (indirect) dependency still pins the vulnerable range — O3 confirms CVE-2026-55252 is resolved across your whole dependency graph.
Workarounds
Stop reflecting attacker-controlled destinations: resolve every redirect target against an allowlist of paths or hosts you own, prefer a server-side key over a full URL in the request, and reject absolute URLs entirely where the flow only ever needs a relative one.

Frequently Asked Questions

### Summary The restrictions on redirect URLs in `openrun` can be bypassed by attackers, leading to open redirect attacks. ### Details In the current project, the referrer header value is used for subsequent redirects, so there is currently a validation for this redirect value. The current validation logic requires that the host and schema of the redirect URL be the same as the current website's URL, and finally, the path part is used for redirection. This check seems robust, but it can still be bypassed by attackers. <img width="1606" height="1346" alt="QQ20260602-140205-2-2" src="https://

O3 Security · Impact-Aware SCA

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