CVE-2018-18926: Code.gitea.io/gitea Remote Code Execution Vulnerability

CRITICAL
Advisory Identifier: GHSA-hf6f-jq25-8gq9
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CVSS 9.8
CWE-94
Published
Advisory Summary

CVE-2018-18926 is a CRITICAL (CVSS 9.8) remote code execution vulnerability (CWE-94: Improper Control of Generation of Code ('Code Injection')) affecting Code.gitea.io/gitea libraries in the Go ecosystem. The issue involves gitea remote code execution (rce). Remediation is available by upgrading affected packages to version 1.5.2.

CVE-2018-18926 at a Glance

CVE Identifier CVE-2018-18926
GHSA Identifier GHSA-hf6f-jq25-8gq9
Severity CRITICAL
CVSS v3.1 Base Score 9.8
CWE Classification CWE-94: Improper Control of Generation of Code ('Code Injection')
Affected Product Code.gitea.io/gitea
Package Ecosystem Go
Published Date
Last Updated

Security Impact

CVSS: 9.8

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:N/S:U/C:H/I:H/A:H).

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 High (C:H)
Integrity High (I:H)
Availability High (A:H)

How to Fix CVE-2018-18926

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: 1.5.2 
Upgrade code.gitea.io/gitea to 1.5.2
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-2018-18926, 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 1.5.2), 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-94: Improper Control of Generation of Code ('Code Injection'), where the product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment. 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 before 1.5.4 allows remote code execution because it does not properly validate session IDs. This is related to session ID handling in the go-macaron/session code for Macaron.

CVE-2018-18926 Affected Code.gitea.io/gitea Versions

1 component(s)
Fixed Versions:
1.5.2
Product / Package Ecosystem Affected Versions Fixed Version
code.gitea.io/gitea
golang/code.gitea.io/gitea
Go
< 1.5.2
1.5.2

References

NVD — CVE-2018-18926 NVD
https://nvd.nist.gov/vuln/detail/CVE-2018-18926
Code.gitea.io/gitea Source Repository REPOSITORY
https://github.com/go-gitea/gitea/issues/5140
Code.gitea.io/gitea Source Repository REPOSITORY
https://github.com/go-gitea/gitea/pull/5177
Security Fix Commit FIX COMMIT
https://github.com/go-gitea/gitea/commit/aeb5655c25053bdcd7eee94ea37df88468374162

Frequently Asked Questions

What is CVE-2018-18926?
CVE-2018-18926 is a security vulnerability in Code.gitea.io/gitea involving Gitea Remote Code Execution (RCE) under CWE-94: Improper Control of Generation of Code ('Code Injection').
Which Code.gitea.io/gitea versions are affected?
Affected versions include releases prior to 1.5.2 across affected packages: code.gitea.io/gitea.
What version fixes CVE-2018-18926?
Upgrading to 1.5.2 (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 1.5.2. Upgrade your dependency to 1.5.2 or later.
What is the CVSS score of CVE-2018-18926?
CVE-2018-18926 has a CVSS v3.1 base score of 9.8 (CRITICAL) with vector string CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H.
What CWE is associated with CVE-2018-18926?
CVE-2018-18926 is classified under CWE-94: Improper Control of Generation of Code ('Code Injection') (The product constructs all or part of a code segment using externally-influenced input from an upstream component, but it does not neutralize or incorrectly neutralizes special elements that could modify the syntax or behavior of the intended code segment.).
How can I check Go dependencies for CVE-2018-18926?
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-hf6f-jq25-8gq9",
  "modified" : "2023-09-15T18:13:45Z",
  "published" : "2022-02-15T01:57:18Z",
  "aliases" : [ "CVE-2018-18926" ],
  "summary" : "Gitea Remote Code Execution (RCE)",
  "details" : "Gitea before 1.5.4 allows remote code execution because it does not properly validate session IDs. This is related to session ID handling in the go-macaron/session code for Macaron.",
  "severity" : [ {
    "type" : "CVSS_V3",
    "score" : "CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H"
  } ],
  "affected" : [ {
    "package" : {
      "ecosystem" : "Go",
      "name" : "code.gitea.io/gitea"
    },
    "ranges" : [ {
      "type" : "ECOSYSTEM",
      "events" : [ {
        "introduced" : "0"
      }, {
        "fixed" : "1.5.2"
      } ]
    } ]
  } ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2018-18926"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/issues/5140"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/pull/5177"
  }, {
    "type" : "WEB",
    "url" : "https://github.com/go-gitea/gitea/commit/aeb5655c25053bdcd7eee94ea37df88468374162"
  } ],
  "database_specific" : {
    "cwe_ids" : [ "CWE-94" ],
    "severity" : "CRITICAL",
    "github_reviewed" : true,
    "github_reviewed_at" : "2021-05-12T18:25:03Z",
    "nvd_published_at" : null
  }
}