Hoppscotch <= 2026.2.1 - Open Redirect

mediumseverity

4.7CVSS score

0.4%likelihood of exploitation, next 30 days

35%of all CVEs are less likely

Readycheck to confirm it

Hoppscotch <= 2026.2.1 is vulnerable to a DOM-based open redirect on the /enter page. The redirect query parameter is passed directly to windowz location.href with no origin validation. Requires one additional query parameter to trigger. Exploited via a crafted URL such as /enter?redirect=evil.com&foo=bar.

Impact

Phishing, credential theft, and OAuth token interception. Victims who click a crafted link see the legitimate Hoppscotch domain in the address bar before being silently redirected to an attacker-controlled site.

Fix

Upgrade to Hoppscotch 2026.3.0 or later. The fix validates that the redirect URL is same-origin before performing the navigation.

How to confirm it

Send: GET {{BaseURL}}/enter?redirect=oast.me&foo=bar
Positive when: matches in header /(?m)^(?:Location\s*?:\s*?)(?:https?:\/\/|\/\/|\/\\\\|\/\\)(?:[a-zA-Z0-9\-_\.@]*…/

Run it with nuclei: nuclei -id CVE-2026-34847 -u <target>

The full check

id: CVE-2026-34847

info:
  name: Hoppscotch <= 2026.2.1 - Open Redirect
  author: ritikchaddha
  severity: medium
  description: |
    Hoppscotch <= 2026.2.1 is vulnerable to a DOM-based open redirect on the /enter page. The redirect query parameter is passed directly to windowz location.href with no origin validation. Requires one additional query parameter to trigger. Exploited via a crafted URL such as /enter?redirect=evil.com&foo=bar.
  impact: |
    Phishing, credential theft, and OAuth token interception. Victims who click a crafted link see the legitimate Hoppscotch domain in the address bar before being silently redirected to an attacker-controlled site.
  remediation: |
    Upgrade to Hoppscotch 2026.3.0 or later. The fix validates that the redirect URL is same-origin before performing the navigation.
  reference:
    - https://github.com/hoppscotch/hoppscotch/security/advisories/GHSA-27pm-c9ch-746q
    - https://nvd.nist.gov/vuln/detail/CVE-2026-34847
  classification:
    cvss-metrics: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:N/I:L/A:N
    cvss-score: 4.7
    cve-id: CVE-2026-34847
    epss-score: 0.00401
    epss-percentile: 0.34727
    cwe-id: CWE-601
  metadata:
    verified: true
    max-request: 1
    vendor: hoppscotch
    product: hoppscotch
    shodan-query: http.title:"Hoppscotch"
    fofa-query: title="Hoppscotch"
  tags: cve,cve2026,hoppscotch,redirect

http:
  - method: GET
    path:
      - "{{BaseURL}}/enter?redirect=oast.me&foo=bar"

    matchers:
      - type: regex
        part: header
        regex:
          - '(?m)^(?:Location\s*?:\s*?)(?:https?:\/\/|\/\/|\/\\\\|\/\\)(?:[a-zA-Z0-9\-_\.@]*)oast\.me\/?(\/|[^.].*)?$'

References

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