Older releases of better_errors open to Cross-Site Request Forgery attack

Not analysed yet

We haven’t published our analysis of this Advisory yet. Once a person has reviewed it, this page will say what’s vulnerable, what has to be true for your app to be affected, and how to check.

Severity and exploitation

• CISA KEV Not listed.
• EPSS 0.0064, the 51st percentile, on 9 Nov 2026: FIRST’s estimate of the chance of exploitation in the next 30 days.

Timeline

This record came from the full history of the GitHub Advisory Database, published 7 Sept 2021. New records show when each source confirmed them.

Sources

• GitHub Advisory Database: GHSA-w3j4-76qw-wwjm
• OSV: GHSA-w3j4-76qw-wwjm
• github.com/BetterErrors/better_errors/security/advisories/GHSA-w3j4-76qw-wwjm
• nvd.nist.gov/vuln/detail/CVE-2021-39197
• github.com/BetterErrors/better_errors/pull/474
• github.com/BetterErrors/better_errors/commit/8e8e796bfbde4aa088741823c8a3fc6df2089bb0
• github.com/BetterErrors/better_errors
• github.com/BetterErrors/better_errors/discussions/507
• github.com/rubysec/ruby-advisory-db/blob/master/gems/better_errors/CVE-2021-39197.yml

Facts on this page come from the GitHub Advisory Database (CC-BY 4.0), OSV and the other sources listed, as published. We don’t reproduce full advisory descriptions, which can contain exploit code.