CVE-2019-8400: Github.com/ory/hydra Cross-Site Scripting Vulnerability

MODERATE
Advisory Identifier: GHSA-7v6r-w4r6-mhch
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CVSS 6.1
CWE-79
Published
Advisory Summary

CVE-2019-8400 is a MODERATE (CVSS 6.1) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Github.com/ory/hydra libraries in the Go ecosystem. The issue involves hydra has reflected xss via error_hint parameter. Remediation is available by upgrading affected packages to version 1.4.8.

CVE-2019-8400 at a Glance

CVE Identifier CVE-2019-8400
GHSA Identifier GHSA-7v6r-w4r6-mhch
Severity MODERATE
CVSS v3.1 Base Score 6.1
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Github.com/ory/hydra
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 6.1

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N).

Attack Vector Network (AV:N)
Attack Complexity Low (AC:L)
Privileges Required None (PR:N)
User Interaction Required (UI:R)
Scope Changed (S:C)
Confidentiality Low (C:L)
Integrity Low (I:L)
Availability None (A:N)

How to Fix CVE-2019-8400

To remediate this vulnerability, upgrade all affected Github.com/ory/hydra dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

github.com/ory/hydra fixed: 1.4.8 
Upgrade github.com/ory/hydra to 1.4.8
Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

inspect dependencies for github.com/ory/hydra

How to Check if You Are Affected

To determine whether your application is affected by CVE-2019-8400, inspect your project dependencies for Github.com/ory/hydra:

inspect dependencies for github.com/ory/hydra

Analyze the terminal output to locate any version of Github.com/ory/hydra in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.4.8), your application is affected.

Note: Verify declared build manifests and deployed runtime container environments.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting'), where the product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users. In Github.com/ory/hydra, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

ORY Hydra before v1.0.0-rc.3+oryOS.9 has Reflected XSS via the oauth2/fallbacks/error error_hint parameter.

CVE-2019-8400 Affected Github.com/ory/hydra Versions

1 component(s)
Fixed Versions:
1.4.8
Product / Package Ecosystem Affected Versions Fixed Version
github.com/ory/hydra
golang/github.com/ory/hydra
Go
< 1.4.8
1.4.8

References

NVD — CVE-2019-8400 NVD
https://nvd.nist.gov/vuln/detail/CVE-2019-8400
Security Fix Commit FIX COMMIT
https://github.com/ory/hydra/commit/9b5bbd48a72096930af08402c5e07fce7dd770f3
hackerone.com/reports/456333 WEB
https://hackerone.com/reports/456333
drive.google.com/file/d/1-25expuyvfk... WEB
https://drive.google.com/file/d/1-25expUYVfK6vsiCmEabUCuelOP7aUDj/view?usp=drivesdk
Github.com/ory/hydra Source Repository REPOSITORY
https://github.com/ory/hydra
Github.com/ory/hydra Source Repository REPOSITORY
https://github.com/ory/hydra/blob/master/CHANGELOG.md#v100-rc3oryos9-2018-12-06
www.youtube.com/watch WEB
https://www.youtube.com/watch?v=RIyZLeKEC8E

Frequently Asked Questions

What is CVE-2019-8400?
CVE-2019-8400 is a security vulnerability in Github.com/ory/hydra involving Hydra has Reflected XSS via error_hint parameter under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Github.com/ory/hydra versions are affected?
Affected versions include releases prior to 1.4.8 across affected packages: github.com/ory/hydra.
What version fixes CVE-2019-8400?
Upgrading to 1.4.8 (or the latest patched release for your respective branch) resolves the vulnerability.
Is github.com/ory/hydra affected?
Yes, github.com/ory/hydra is affected in releases prior to 1.4.8. Upgrade your dependency to 1.4.8 or later.
What is the CVSS score of CVE-2019-8400?
CVE-2019-8400 has a CVSS v3.1 base score of 6.1 (MODERATE) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N.
What CWE is associated with CVE-2019-8400?
CVE-2019-8400 is classified under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting') (The product does not neutralize or incorrectly neutralizes user-controllable input before it is placed in output that is used as a web page that is served to other users.).
How can I check Go dependencies for CVE-2019-8400?
Run the dependency tree command: 'inspect dependencies for github.com/ory/hydra'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-7v6r-w4r6-mhch",
  "modified" : "2026-03-26T18:20:05Z",
  "published" : "2022-05-14T01:33:08Z",
  "aliases" : [ "CVE-2019-8400" ],
  "summary" : "Hydra has Reflected XSS via error_hint parameter",
  "details" : "ORY Hydra before v1.0.0-rc.3+oryOS.9 has Reflected XSS via the oauth2/fallbacks/error error_hint parameter.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:C/C:L/I:L/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "github.com/ory/hydra"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.4.8"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2019-8400"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ory/hydra/commit/9b5bbd48a72096930af08402c5e07fce7dd770f3"
  }, {
    "type" : "WEB",
    "url" : "https://hackerone.com/reports/456333"
  }, {
    "type" : "WEB",
    "url" : "https://drive.google.com/file/d/1-25expUYVfK6vsiCmEabUCuelOP7aUDj/view?usp=drivesdk"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/ory/hydra"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/ory/hydra/blob/master/CHANGELOG.md#v100-rc3oryos9-2018-12-06"
  }, {
    "type" : "WEB",
    "url" : "https://www.youtube.com/watch?v=RIyZLeKEC8E"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "MODERATE",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-26T18:20:05Z",
    "nvd_published_at" : "2019-02-17T06:29:00Z"
  }
}