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GHSA-5qhx-gwfj-6jqr CVE-2026-23632 GO-2026-4450

Gogs user can update repository content with read-only permission

Medium Go
Severity
6.5 / 10
Medium · CVSS 3.1
Exploit chance (EPSS)
0.32%
Chance of exploitation in the next 30 days. Higher than 24.70% of scored vulnerabilities.
Known exploited
No
Not in CISA's catalog
Weakness
CWE-862 Missing Authorization
CWE-863 Incorrect Authorization
Fix
0.13.4
Upgrade gogs.io/gogs to this version or later

Description

Vulnerability Description

The endpoint PUT /repos/:owner/:repo/contents/* does not require write permissions and allows access with read permission only via repoAssignment().

After passing the permission check, PutContents() invokes UpdateRepoFile(), which results in:

  • Commit creation
  • Execution of git push

As a result, a token with read-only permission can be used to modify repository contents.


Attack Prerequisites

  • Possession of a valid access token
  • Read permission on the target repository (public repository or collaborator with read access)

Attack Scenario

  1. The attacker accesses the target repository with a read-only token
  2. The attacker sends a PUT /contents request to update an arbitrary file
  3. The server creates a commit and performs a git push on behalf of the attacker

Potential Impact

  • Source code tampering
  • Injection of backdoors
  • Compromise of release artifacts and distributed packages

Affected versions

Go

PackageVulnerableFixed in
gogs.io/gogs
< 0.13.4
0.13.4
gogs.io/gogs
all versions
No fix yet

How to fix

Move to the fixed version or later with your package manager, update the lockfile, and run your tests. If the package only arrives through another dependency, upgrade that dependency first. If none of its releases pulls a fixed version yet, force the version with your package manager's override.

gogs.io/gogs Go → 0.13.4

go
go get gogs.io/gogs@v0.13.4 && go mod tidy

Severity breakdown

CVSS 3.1 6.5

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:N/I:H/A:N

Attack vector
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
High
Availability
None

Weakness

CWE-862: Missing Authorization

The product does not perform an authorization check when an actor attempts to access a resource or perform an action.

How to prevent it
  • Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
  • Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
  • Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
  • System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

CWE-863: Incorrect Authorization

The product performs an authorization check when an actor attempts to access a resource or perform an action, but it does not correctly perform the check.

How to prevent it
  • Architecture and Design: Divide the product into anonymous, normal, privileged, and administrative areas. Reduce the attack surface by carefully mapping roles with data and functionality. Use role-based access control (RBAC) [REF-229] to enforce the roles at the appropriate boundaries. Note that this approach may not protect against horizontal authorization, i.e., it will not protect a user from attacking others with the same role.
  • Architecture and Design: Ensure that access control checks are performed related to the business logic. These checks may be different than the access control checks that are applied to more generic resources such as files, connections, processes, memory, and database records. For example, a database may restrict access for medical records to a specific database user, but each record might only be intended to be accessible to the patient and the patient's doctor [REF-7].
  • Architecture and Design: Use a vetted library or framework that does not allow this weakness to occur or provides constructs that make this weakness easier to avoid. For example, consider using authorization frameworks such as the JAAS Authorization Framework [REF-233] and the OWASP ESAPI Access Control feature [REF-45].
  • Architecture and Design: For web applications, make sure that the access control mechanism is enforced correctly at the server side on every page. Users should not be able to access any unauthorized functionality or information by simply requesting direct access to that page. One way to do this is to ensure that all pages containing sensitive information are not cached, and that all such pages restrict access to requests that are accompanied by an active and authenticated session token associated with a user who has the required permissions to access that page.
  • System Configuration, Installation: Use the access control capabilities of your operating system and server environment and define your access control lists accordingly. Use a "default deny" policy when defining these ACLs.

References

Timeline

  1. Published
  2. Last updated by the source
  3. Latest EPSS score
AdvisorySeverityWhy it's related
GHSA-mq8m-42gh-wq7r
Gogs vulnerable to a bypass of CVE-2024-55947
High Known exploited Also affects gogs.io/gogs
GHSA-3w28-36p9-w929
Gogs's Unauthenticated Jupyter Notebook (ipynb) Sanitizer allows arbitrary data: URIs leading to XSS
Medium Also affects gogs.io/gogs
GHSA-744x-3838-5r56
Gogs Vulnerable to Unauthenticated Organization Teams Information Disclosure via API
Medium Also affects gogs.io/gogs
GHSA-xp79-5mx3-jx52
Gogs has Unauthenticated Asymmetric Denial of Service (DoS) via SSH Handshake Stall (File Descriptor Exhaustion)
Medium Also affects gogs.io/gogs
GHSA-c39w-43gm-34h5
Gogs has Path Traversal in organization name that results in RCE through Git hooks
Critical Also affects gogs.io/gogs
GHSA-6p9m-q3jp-47h4
Gogs: LFS dedupe path leaks private repo content across tenants
High Also affects gogs.io/gogs
GHSA-89mr-xqfv-758m
Gogs: UploadRepoFiles writes outside repo working tree via committed parent sym
Critical Also affects gogs.io/gogs
GHSA-wmfg-5p4h-5fw3
Gogs allows users to write to readonly repositories using receive-pack + service=git-upload-pack confusion
High Also affects gogs.io/gogs
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