CVE-2026-75106: OpnForm Editable Submission Secret Derivation via Empty Hashids Salt

Severity: critical (CVSS 9.1 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: none known
Published: 2026-08-17 · updated 2026-10-01
Weakness: CWE-340

Description

OpnForm derives editable-submission secrets from sequential row identifiers using Hashids with an empty default salt, allowing unauthenticated attackers to compute hashes for any submission. Attackers can read other respondents' full submission data through the submission-fetch endpoint or overwrite submissions by supplying predicted hashes to the answer endpoint.

Affected products

OpnForm: before 2.0.2 — fixed in 2.0.2

How to fix

Upgrade to a fixed version: OpnForm 2.0.2. Check the vendor advisory for mitigations.

References

https://github.com/OpnForm/OpnForm
https://github.com/OpnForm/OpnForm/commit/6c67ff0a9bc0ac27ae26b32b8e108a176f8161b1
https://github.com/OpnForm/OpnForm/issues/1259
https://github.com/OpnForm/OpnForm/releases/tag/v2.0.2
https://www.vulncheck.com/advisories/opnform-editable-submission-secret-derivation-via-empty-hashids-salt
https://github.com/OpnForm/OpnForm/issues/1259

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