GHSA-2c6v-8r3v-gh6p

Опубликовано: 17 фев. 2026

Источник: github

Github: Прошло ревью

CVSS4: 7.1

Описание

Gogs has a Protected Branch Deletion Bypass in Web Interface

Summary

An access control bypass vulnerability in Gogs web interface allows any repository collaborator with Write permissions to delete protected branches (including the default branch) by sending a direct POST request, completely bypassing the branch protection mechanism. This vulnerability enables privilege escalation from Write to Admin level, allowing low-privilege users to perform dangerous operations that should be restricted to administrators only.

Although Git Hook layer correctly prevents protected branch deletion via SSH push, the web interface deletion operation does not trigger Git Hooks, resulting in complete bypass of protection mechanisms.

Details

Affected Component

File: internal/route/repo/branch.go
Function: DeleteBranchPost (lines 110-155)
Route Configuration: internal/cmd/web.go:589
m.Post("/delete/*", reqSignIn, reqRepoWriter, repo.DeleteBranchPost)

Root Cause

The DeleteBranchPost function performs the following checks when deleting a branch:

✅ User authentication (reqSignIn)
✅ Write permission check (reqRepoWriter)
✅ Branch existence verification
✅ CommitID matching (optional parameter)
❌ Missing protected branch check
❌ Missing default branch check

While the UI layer (internal/route/repo/issue.go:646-658) correctly checks protected branch status and hides the delete button, attackers can directly construct POST requests to bypass UI restrictions.

Vulnerable Code

Vulnerable implementation (internal/route/repo/branch.go:110-155):

func DeleteBranchPost(c *context.Context) { branchName := c.Params("*") commitID := c.Query("commit") defer func() { redirectTo := c.Query("redirect_to") if !tool.IsSameSiteURLPath(redirectTo) { redirectTo = c.Repo.RepoLink } c.Redirect(redirectTo) }() if !c.Repo.GitRepo.HasBranch(branchName) { return } if len(commitID) > 0 { branchCommitID, err := c.Repo.GitRepo.BranchCommitID(branchName) if err != nil { log.Error("Failed to get commit ID of branch %q: %v", branchName, err) return } if branchCommitID != commitID { c.Flash.Error(c.Tr("repo.pulls.delete_branch_has_new_commits")) return } } // 🔴 Vulnerability: Missing protected branch check here // Should add check like: // protectBranch, err := database.GetProtectBranchOfRepoByName(c.Repo.Repository.ID, branchName) // if protectBranch != nil && protectBranch.Protected { ... } if err := c.Repo.GitRepo.DeleteBranch(branchName, git.DeleteBranchOptions{ Force: true, }); err != nil { log.Error("Failed to delete branch %q: %v", branchName, err) return } if err := database.PrepareWebhooks(c.Repo.Repository, database.HookEventTypeDelete, &api.DeletePayload{ Ref: branchName, RefType: "branch", PusherType: api.PUSHER_TYPE_USER, Repo: c.Repo.Repository.APIFormatLegacy(nil), Sender: c.User.APIFormat(), }); err != nil { log.Error("Failed to prepare webhooks for %q: %v", database.HookEventTypeDelete, err) return } }

Correct implementation in Git Hook (internal/cmd/hook.go:122-125):

// check and deletion if newCommitID == git.EmptyID { fail(fmt.Sprintf("Branch '%s' is protected from deletion", branchName), "") }

Correct UI layer check (internal/route/repo/issue.go:646-658):

protectBranch, err := database.GetProtectBranchOfRepoByName(pull.BaseRepoID, pull.HeadBranch) if err != nil { if !database.IsErrBranchNotExist(err) { c.Error(err, "get protect branch of repository by name") return } } else { branchProtected = protectBranch.Protected } c.Data["IsPullBranchDeletable"] = pull.BaseRepoID == pull.HeadRepoID && c.Repo.IsWriter() && c.Repo.GitRepo.HasBranch(pull.HeadBranch) && !branchProtected // UI layer has check, but backend doesn't

PoC

Prerequisites

Have Write permissions to the target repository (collaborator or team member)
Target repository has protected branches configured (e.g., main, master, develop)
Access to Gogs web interface

Send Malicious POST Request

# Directly send DELETE request bypassing UI protection curl -X POST \ -b cookies.txt \ -H "Content-Type: application/x-www-form-urlencoded" \ -d "_csrf=YOUR_CSRF_TOKEN" \ "https://gogs.example.com/username/repo/branches/delete/main"

Impact

Bypass branch protection mechanism: The core function of protected branches is to prevent deletion, and this vulnerability completely undermines this mechanism
Delete default branch: Can cause repository to become inaccessible (git clone/pull failures)
Bypass code review: After deleting protected branch, can push new branch bypassing Pull Request requirements
Privilege escalation: Writer permission users can perform operations that should only be allowed for Admins

Ссылки

Пакеты

Наименование

gogs.io/gogs

Затронутые версииВерсия исправления

< 0.14.1

0.14.1

EPSS

Процентиль: 13%

0.00043

Низкий

7.1 High

CVSS4

CVE ID

CVE-2026-25232

Дефекты

CWE-863

Связанные уязвимости

CVE-2026-25232

CVSS3: 8.8

nvd

около 2 месяцев назад

Gogs is an open source self-hosted Git service. Versions 0.13.4 and below have an access control bypass vulnerability which allows any repository collaborator with Write permissions to delete protected branches (including the default branch) by sending a direct POST request, completely bypassing the branch protection mechanism. This vulnerability in the DeleteBranchPost function eenables privilege escalation from Write to Admin level, allowing low-privilege users to perform dangerous operations that should be restricted to administrators only. Although Git Hook layer correctly prevents protected branch deletion via SSH push, the web interface deletion operation does not trigger Git Hooks, resulting in complete bypass of protection mechanisms. In oder to exploit this vulnerability, attackers must have write permissions to the target repository, protected branches configured to the target repository and access to the Gogs web interface. This issue has been fixed in version 0.14.1.

EPSS

Процентиль: 13%

0.00043

Низкий

7.1 High

CVSS4

CVE ID

CVE-2026-25232

Дефекты

CWE-863