CVE-2026-34931: hoppscotch: Improper loopback redirect_uri validation in device-login flow

Severity: critical (CVSS 9.6 v3.1)
Exploited in the wild: not listed in CISA KEV
EPSS: 0.4% probability of exploitation in the next 30 days
Public exploit or detection template: yes
Published: 2026-04-02 · updated 2026-07-24
Weakness: CWE-601

Description

hoppscotch is an open source API development ecosystem. Prior to version 2026.3.0, there is an open redirect vulnerability that leads to token exfiltration. With these tokens, the attacker can sign in as the victim to takeover their account. This issue has been patched in version 2026.3.0.

Affected products

hoppscotch: before 2026.3.0 — fixed in 2026.3.0

How to fix

Upgrade to a fixed version: hoppscotch 2026.3.0. Check the vendor advisory for mitigations.

References

https://github.com/hoppscotch/hoppscotch/releases/tag/2026.3.0
https://github.com/hoppscotch/hoppscotch/security/advisories/GHSA-7fg7-wx5q-6m3v

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