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Fencer Vulns
critical 9.6

CVE-2026-34931 json

hoppscotch: Improper loopback redirect_uri validation in device-login flow

published 2026-04-02 7 mo ago modified 2026-07-24 3 mo ago also EUVD-2026-18538

cvss
9.6
version 3.1, NVD
cisa kev
Not listed
not in CISA's catalog
epss
0.4%
EPSS 0.4% chance of exploitation in 30 days, percentile 32%
public exploits
0
none known

Summary

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.

Patch / fix

  • hoppscotch hoppscotch 2026.3.0

CISA SSVC

Exploitation
Proof of concept is public
Automatable
no
Technical impact
total
Assessed
7 mo ago

Exploit prediction

0.38% chance of exploitation in the next 30 days, higher than 32% of all scored CVEs (FIRST EPSS, 2026-11-08).

Exploits and checks

  • github.com https://github.com/hoppscotch/hoppscotch/security/advisories/GHSA-7fg7-wx5q-6m3v referenced PoC, tagged "exploit" by a source, unverified

CVSS scores

assigned by version score vector
CNA 4.0 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N
CNA 4.0 8.5 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:A/VC:H/VI:H/VA:N/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
NVD 3.1 9.6 CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:C/C:H/I:H/A:H

Affected products

  • hoppscotch hoppscotch

Classification

Weakness
  • CWE-601 URL Redirection to Untrusted Site

References

Sources

Fencer Vulns keeps one entry per vulnerability: the CVE id wins, then GHSA, and records that alias each other are merged, except that two CVEs always keep separate entries. The same data is available as JSON.

CPEs and fixed versions use Anchore's correction of NVD's data: Added CPE configurations because not yet analyzed by NVD.