CVE-2026-27657: Code.gitea.io/gitea Gitea Primary Email Ownership Bypass Vulnerability

HIGH
Advisory Identifier: GHSA-4c8f-3m6h-m56r
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CVSS 7.5
CWE-639
Published
Advisory Summary

CVE-2026-27657 is a HIGH (CVSS 7.5) gitea primary email ownership bypass vulnerability (CWE-639: Authorization Bypass Through User-Controlled Key) affecting Code.gitea.io/gitea libraries in the Go ecosystem. The issue involves gitea primary email ownership bypass allows cross-user email changes. Remediation is available by upgrading affected packages to version 1.25.5.

CVE-2026-27657 at a Glance

CVE Identifier CVE-2026-27657
GHSA Identifier GHSA-4c8f-3m6h-m56r
Severity HIGH
CVSS v3.1 Base Score 7.5
CWE Classification CWE-639: Authorization Bypass Through User-Controlled Key
Affected Product Code.gitea.io/gitea
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 7.5

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

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

How to Fix CVE-2026-27657

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

code.gitea.io/gitea fixed: 1.25.5 
Upgrade code.gitea.io/gitea to 1.25.5
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 code.gitea.io/gitea

How to Check if You Are Affected

To determine whether your application is affected by CVE-2026-27657, inspect your project dependencies for Code.gitea.io/gitea:

inspect dependencies for code.gitea.io/gitea

Analyze the terminal output to locate any version of Code.gitea.io/gitea in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than 1.25.5), 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-639: Authorization Bypass Through User-Controlled Key, where the system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data. In Code.gitea.io/gitea, 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

Gitea versions before 1.25.5 allow a user to change another user's primary email address.

CVE-2026-27657 Affected Code.gitea.io/gitea Versions

1 component(s)
Fixed Versions:
1.25.5
Product / Package Ecosystem Affected Versions Fixed Version
code.gitea.io/gitea
golang/code.gitea.io/gitea
Go
< 1.25.5
1.25.5

References

NVD — CVE-2026-27657 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-27657
Code.gitea.io/gitea Source Repository REPOSITORY
https://github.com/go-gitea/gitea/pull/36586
Code.gitea.io/gitea Source Repository REPOSITORY
https://github.com/go-gitea/gitea/pull/36607
Security Fix Commit FIX COMMIT
https://github.com/go-gitea/gitea/commit/8d26ea93738430a57d00c2da0fd97e1ba712eed7
Security Fix Commit FIX COMMIT
https://github.com/go-gitea/gitea/commit/e927a86586afc138959b462d4040d1547f406f71
blog.gitea.com/release-of-1.25.5 WEB
https://blog.gitea.com/release-of-1.25.5
Code.gitea.io/gitea Source Repository REPOSITORY
https://github.com/go-gitea/gitea
Code.gitea.io/gitea Release RELEASE
https://github.com/go-gitea/gitea/releases/tag/v1.25.5

Frequently Asked Questions

What is CVE-2026-27657?
CVE-2026-27657 is a security vulnerability in Code.gitea.io/gitea involving Gitea primary email ownership bypass allows cross-user email changes under CWE-639: Authorization Bypass Through User-Controlled Key.
Which Code.gitea.io/gitea versions are affected?
Affected versions include releases prior to 1.25.5 across affected packages: code.gitea.io/gitea.
What version fixes CVE-2026-27657?
Upgrading to 1.25.5 (or the latest patched release for your respective branch) resolves the vulnerability.
Is code.gitea.io/gitea affected?
Yes, code.gitea.io/gitea is affected in releases prior to 1.25.5. Upgrade your dependency to 1.25.5 or later.
What is the CVSS score of CVE-2026-27657?
CVE-2026-27657 has a CVSS v3.1 base score of 7.5 (HIGH) with vector string CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N.
What CWE is associated with CVE-2026-27657?
CVE-2026-27657 is classified under CWE-639: Authorization Bypass Through User-Controlled Key (The system's authorization functionality does not prevent one user from gaining access to another user's data or record by modifying the key value identifying the data.).
How can I check Go dependencies for CVE-2026-27657?
Run the dependency tree command: 'inspect dependencies for code.gitea.io/gitea'. 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-4c8f-3m6h-m56r",
  "modified" : "2026-09-01T17:21:17Z",
  "published" : "2026-07-03T21:31:37Z",
  "aliases" : [ "CVE-2026-27657" ],
  "summary" : "Gitea primary email ownership bypass allows cross-user email changes",
  "details" : "Gitea versions before 1.25.5 allow a user to change another user's primary email address.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:N"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "code.gitea.io/gitea"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.25.5"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-27657"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/pull/36586"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/pull/36607"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/commit/8d26ea93738430a57d00c2da0fd97e1ba712eed7"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/commit/e927a86586afc138959b462d4040d1547f406f71"
  }, {
    "type" : "WEB",
    "url" : "https://blog.gitea.com/release-of-1.25.5"
  }, {
    "type" : "PACKAGE",
    "url" : "https://github.com/go-gitea/gitea"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/releases/tag/v1.25.5"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-639" ],
    "severity" : "HIGH",
    "github_reviewed" : true,
    "github_reviewed_at" : "2026-09-01T17:21:17Z",
    "nvd_published_at" : "2026-07-03T21:16:58Z"
  }
}