User redirection via prefix-only state validation
Published Feb 19, 2026 · Updated Feb 19, 2026
Open redirect in Busy 2.5.0 through 2.5.5 allows remote authenticated users to send victims to attacker-controlled sites via /callback. The callback handler accepts the state query value, checks only that its first character is a slash, and passes the result directly to res.redirect. A valid access token and expiry value plus victim interaction are required; a crafted protocol-relative path can support phishing.
Summary
What happened
Open redirect in Busy 2.5.0 through 2.5.5 allows remote authenticated users to send victims to attacker-controlled sites via /callback. The callback handler accepts the state query value, checks only that its first character is a slash, and passes the result directly to res.redirect. A valid access token and expiry value plus victim interaction are required; a crafted protocol-relative path can support phishing.
The record
- CVE
- CVE-2026-2709
- Published
- Feb 19, 2026
- Updated
- Feb 19, 2026
- Vendor
- Busy.org
- Product
- Busy
- Classifications
- CWE-601, T1204.001
- Attack vector
- network
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 19, 2026CVE publishedPublication date reported by the CVE source.
- Feb 19, 2026Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=2.5.0
- Affected versionversion=2.5.1
- Affected versionversion=2.5.2
- Affected versionversion=2.5.3
- Affected versionversion=2.5.4
- Affected versionversion=2.5.5
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Busy callback open-redirect proof of conceptproof of concept · unverified
Labels summarize the accepted research assessment. They do not indicate a test against your environment.
Technologies
Your stack
See the directory against your own environment.
Your stack
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