VulnerabilityPublished 9 Jul 2026

CVE-2026-55252: OpenRun · Redirect URL validation bypass using //host paths leads to Open Redirect

Affects github.com/openrundev/openrunSource GCVE Database

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Authoritative record:CVE-2026-55252· Medium 5.1

Not known to be exploited · CVSS 5.1 Medium : upgrade to 0.17.7 when convenient.

Data as of 30 Oct 2026, 06:59 UTC

CVSS 4.0 base score

5.1Medium

How severe the flaw is on the 0–10 CVSS scale.

EPSS: 0.4% chance of exploitation in 30 days – higher than 35% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.
Patch: Available – fixed in 0.17.7

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:N/VI:N/VA:N/SC:L/SI:N/SA:N

Attack Vector: Network
Attack Complexity: Low
Attack Requirements: None
Privileges Required: None
User Interaction: Active
Vulnerable system confidentiality: None
Vulnerable system integrity: None
Vulnerable system availability: None
Subsequent system confidentiality: Low
Subsequent system integrity: None
Subsequent system availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable system is bound to the network stack and the set of possible attackers extends beyond the other options listed below, up to and including the entire Internet. Such a vulnerability is often termed “remotely exploitable” and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: The attacker must take no measurable action to exploit the vulnerability. The attack requires no target-specific circumvention to exploit the vulnerability. An attacker can expect repeatable success against the vulnerable system.
Attack Requirements: None: The successful attack does not depend on the deployment and execution conditions of the vulnerable system. The attacker can expect to be able to reach the vulnerability and execute the exploit under all or most instances of the vulnerability.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files of the vulnerable system to carry out an attack.
User Interaction: Active: Successful exploitation of this vulnerability requires a targeted user to perform specific, conscious interactions with the vulnerable system and the attacker’s payload, or the user’s interactions would actively subvert protection mechanisms which would lead to exploitation of the vulnerability.
Vulnerable system confidentiality: None: There is no loss of confidentiality within the Vulnerable System.
Vulnerable system integrity: None: There is no loss of integrity within the Vulnerable System.
Vulnerable system availability: None: There is no impact to availability within the Vulnerable System.
Subsequent system confidentiality: Low: There is some loss of confidentiality. Access to some restricted information is obtained, but the attacker does not have control over what information is obtained, or the amount or kind of loss is limited. The information disclosure does not cause a direct, serious loss to the Subsequent System.
Subsequent system integrity: None: There is no loss of integrity within the Subsequent System or all integrity impact is constrained to the Vulnerable System.
Subsequent system availability: None: There is no impact to availability within the Subsequent System or all availability impact is constrained to the Vulnerable System.

Definitions: FIRST CVSS v4.0 specification.

Exploitation evidence

t = 0 is the CVE’s publication on cve.org

Disclosed: evidence found.
CVE published 1 Oct 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponized: evidence found.
CISA SSVC: proof of concept public
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

CVE ID reserved
by GitHub, Inc.
16 Jun 202616:44 UTC, 107 days before disclosure
CVE published
on cve.org
1 Oct 202619:52 UTC, t = 0
CISA SSVC assessment
proof of concept public
1 Oct 202620:02 UTC, 10 minutes after disclosure
In Threat Radar
record ingested
26 Oct 202608:14 UTC, 25 days after disclosure

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), CISA SSVC, the Metasploit, Exploit-DB and nuclei-templates index as of 29 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponized: A Metasploit exploit module or Exploit-DB entry exists (Metasploit scanner modules do not count), or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade github.com/openrundev/openrun to 0.17.7.

Affected software

Product	Affected	Fixed in
Gogithub.com/openrundev/openrun	Affected <0.17.7	Fixed in 0.17.7

Check your own hosts for these packages with threat-finder (opens in a new tab), our free open-source scanner.

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. <img width="1606" height="1346" alt="QQ20260602-140205-2-2" src="https://github.com/user-attachments/assets/83c549f3-38d7-444d-90f0-131d806f67ff" /> 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. <img width="1587" height="717" alt="QQ20260602-140756-2-3" src="https://github.com/user-attachments/assets/51430c42-bd10-401b-9c9f-27a91a0bc648" /> 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 ``` <img width="1536" height="729" alt="QQ20260602-140925-2-4" src="https://github.com/user-attachments/assets/31fde919-5f90-409f-8b14-af6c9c71761b" /> The user was then successfully redirected to the external address `http://fushuling.com`. <img width="1692" height="855" alt="QQ20260602-141005-2-5" src="https://github.com/user-attachments/assets/83b43ef6-52fa-4218-908b-7795394ae707" /> ### PoC ``` http://127.0.0.1:25222//fushuling.com ``` ### Impact Open Redirect

CWE-601URL Redirection to Untrusted Site (Open Redirect) (opens in a new tab)
Base weaknessLikelihood of exploit: LowOWASP Top 10 A01:2025: Broken Access Control (opens in a new tab)
The web application accepts a user-controlled input that specifies a link to an external site, and uses that link in a redirect.
Implementation · Input Validation
Assume all input is malicious. Use an "accept known good" input validation strategy, i.e., use a list of acceptable inputs that strictly conform to specifications. Reject any input that does not strictly conform to specifications, or transform it into something that does.
Architecture and Design
Use an intermediate disclaimer page that provides the user with a clear warning that they are leaving the current site. Implement a long timeout before the redirect occurs, or force the user to click on the link. Be careful to avoid XSS problems (CWE-79) when generating the disclaimer page.
Architecture and Design · Enforcement by Conversion
When the set of acceptable objects, such as filenames or URLs, is limited or known, create a mapping from a set of fixed input values (such as numeric IDs) to the actual filenames or URLs, and reject all other inputs.
OWASP Cheat Sheets
Mass Assignment (opens in a new tab)
Authorization (opens in a new tab)
OWASP ASVS 4.0.3
V5.1.5 (opens in a new tab)
Attack patterns
Cross-Site Flashing (opens in a new tab)
From MITRE CWE, MITRE CAPEC and OWASP (Top 10, OpenCRE).

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Description

WeaknessesCWE-601

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