---
id: CVE-2026-26247
title: >-
  Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge
  method correctly during authorization, allowing token exchange without the
  expected verifier check.
summary: >-
  Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge
  method correctly during authorization, allowing token exchange without the
  expected verifier check.
severity: none
cwe:
  - CWE-284
published: '2026-07-03'
updated: '2026-07-03'
source: NVD
sourceUrl: 'https://nvd.nist.gov/vuln/detail/CVE-2026-26247'
references:
  - url: 'https://blog.gitea.com/release-of-1.25.5/'
    label: 88ee5874-cf24-4952-aea0-31affedb7ff2
  - url: 'https://github.com/go-gitea/gitea/pull/36462'
    label: 88ee5874-cf24-4952-aea0-31affedb7ff2
  - url: 'https://github.com/go-gitea/gitea/pull/36477'
    label: 88ee5874-cf24-4952-aea0-31affedb7ff2
  - url: 'https://github.com/go-gitea/gitea/releases/tag/v1.25.5'
    label: 88ee5874-cf24-4952-aea0-31affedb7ff2
tags:
  - nvd
epss: 0.00495
epssPercentile: 0.39826
ingestedAt: '2026-07-04T13:56:12.134Z'
---

## Overview

Gitea versions before 1.25.5 do not persist the OAuth2 PKCE S256 challenge method correctly during authorization, allowing token exchange without the expected verifier check.

## Remediation

Refer to the linked advisories for vendor-supplied fixes and affected version ranges.