CVE-2026-26276: Gogs Cross-Site Scripting Vulnerability

HIGH
Advisory Identifier: GHSA-vgjm-2cpf-4g7c
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CVSS 7.3
CWE-79
Published
Advisory Summary

CVE-2026-26276 is a HIGH (CVSS 7.3) cross-site scripting vulnerability (CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')) affecting Gogs libraries in the Go ecosystem. The issue involves dom-based xss via milestone selection. Remediation is available in the latest vendor maintenance releases.

CVE-2026-26276 at a Glance

CVE Identifier CVE-2026-26276
GHSA Identifier GHSA-vgjm-2cpf-4g7c
Severity HIGH
CVSS v3.1 Base Score 7.3
CWE Classification CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')
Affected Product Gogs
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.3

The security impact metrics below are parsed directly from the CVSS v3.1 vector string (CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N).

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

How to Fix CVE-2026-26276

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

gogs.io/gogs fixed: Latest secure release 
Upgrade gogs.io/gogs to Latest secure release
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 gogs.io/gogs

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-26276, inspect your project dependencies for Gogs:

inspect dependencies for gogs.io/gogs

Analyze the terminal output to locate any version of Gogs in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), 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 Gogs, 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

# Summary It was confirmed in a test environment that an attacker can store an HTML/JavaScript payload in a repository’s **Milestone name**, and when another user selects that Milestone on the **New Issue** page (`/issues/new`), a **DOM-Based XSS** is triggered. # Impact * Theft of information accessible in the victim’s session. * Extraction of CSRF tokens and submission of state-changing requests with the victim’s privileges. * Repository operations performed with the victim’s privileges (Issue operations, settings changes, etc.). (The impact scope depends on the victim’s permission level.) # Remediation A fix is available at https://github.com/gogs/gogs/releases/tag/v0.14.2

CVE-2026-26276 Affected Gogs Versions

1 component(s)
Product / Package Ecosystem Affected Versions Fixed Version
gogs.io/gogs
golang/gogs.io/gogs
Go
≤ 0.13.3

References

NVD — CVE-2026-26276 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-26276
GitHub Advisory / Wiki ADVISORY
https://github.com/gogs/gogs/security/advisories/GHSA-vgjm-2cpf-4g7c
Gogs Source Repository REPOSITORY
https://github.com/gogs/gogs/pull/8178
Security Fix Commit FIX COMMIT
https://github.com/gogs/gogs/commit/9001a68cdda7bd9c078ffd6d1c4622905ac11e5c
Gogs Source Repository REPOSITORY
https://github.com/gogs/gogs
Gogs Release RELEASE
https://github.com/gogs/gogs/releases/tag/v0.14.2

Frequently Asked Questions

What is CVE-2026-26276?
CVE-2026-26276 is a security vulnerability in Gogs involving DOM-based XSS via milestone selection under CWE-79: Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting').
Which Gogs versions are affected?
Affected versions include releases prior to current release patches across affected packages: gogs.io/gogs.
What version fixes CVE-2026-26276?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
Is gogs.io/gogs affected?
Yes, gogs.io/gogs is affected in releases prior to Latest secure release. Upgrade your dependency to Latest secure release or later.
What is the CVSS score of CVE-2026-26276?
CVE-2026-26276 has a CVSS v3.1 base score of 7.3 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N.
What CWE is associated with CVE-2026-26276?
CVE-2026-26276 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-2026-26276?
Run the dependency tree command: 'inspect dependencies for gogs.io/gogs'. 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-vgjm-2cpf-4g7c",
  "modified" : "2026-03-05T22:28:52Z",
  "published" : "2026-03-05T20:16:20Z",
  "aliases" : [ "CVE-2026-26276" ],
  "summary" : "Gogs: DOM-based XSS via milestone selection",
  "details" : "# Summary\n\nIt was confirmed in a test environment that an attacker can store an HTML/JavaScript payload in a repository’s **Milestone name**, and when another user selects that Milestone on the **New Issue** page (`/issues/new`), a **DOM-Based XSS** is triggered.\n\n# Impact\n\n* Theft of information accessible in the victim’s session.\n* Extraction of CSRF tokens and submission of state-changing requests with the victim’s privileges.\n* Repository operations performed with the victim’s privileges (Issue operations, settings changes, etc.).\n\n(The impact scope depends on the victim’s permission level.)\n\n# Remediation\n\nA fix is available at https://github.com/gogs/gogs/releases/tag/v0.14.2",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:H/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "gogs.io/gogs"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "last_affected" : "0.13.3"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "WEB",
    "url" : "https://github.com/gogs/gogs/security/advisories/GHSA-vgjm-2cpf-4g7c"
  }, {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-26276"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/gogs/gogs/pull/8178"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/gogs/gogs/commit/9001a68cdda7bd9c078ffd6d1c4622905ac11e5c"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/gogs/gogs"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/gogs/gogs/releases/tag/v0.14.2"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-79" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-03-05T20:16:20Z",
    "nvd_published_at" : "2026-03-05T19:16:04Z"
  }
}