CVE-2026-25120

EUVD-2026-8122 · Published Feb 17, 2026

Gogs Allows Cross-Repository Comment Deletion via DeleteComment

IDOR: Cross-Repository Comment Deletion via DeleteComment

Summary

The POST /:owner/:repo/issues/comments/:id/delete endpoint does not verify that the comment belongs to the repository specified in the URL. This allows a repository administrator to delete comments from any other repository by supplying arbitrary comment IDs, bypassing authorization controls.

Vulnerability Details

Field	Value
Affected File	`internal/route/repo/issue.go`
Affected Function	`DeleteComment` (lines 955-968)
Secondary File	`internal/database/comment.go`
Secondary Function	`DeleteCommentByID` (lines 505-520)

Root Cause

The vulnerability exists due to insufficient authorization validation in the comment deletion flow:

1. Missing Repository Ownership Check in DeleteComment

In internal/route/repo/issue.go, the function retrieves a comment by ID without verifying repository ownership:

func DeleteComment(c *context.Context) {
    comment, err := database.GetCommentByID(c.ParamsInt64(":id"))
    if err != nil {
        c.NotFoundOrError(err, "get comment by ID")
        return
    }

    // Only checks if user is comment poster OR admin of the CURRENT repo (from URL)
    if c.UserID() != comment.PosterID && !c.Repo.IsAdmin() {
        c.NotFound()
        return
    } else if comment.Type != database.CommentTypeComment {
        c.Status(http.StatusNoContent)
        return
    }

    // No verification that comment.IssueID belongs to c.Repo.Repository.ID!
    if err = database.DeleteCommentByID(c.User, comment.ID); err != nil {
        c.Error(err, "delete comment by ID")
        return
    }

    c.Status(http.StatusOK)
}

2. Database Layer Performs No Authorization

In internal/database/comment.go, the deletion function performs no repository validation:

func DeleteCommentByID(doer *User, id int64) error {
    comment, err := GetCommentByID(id)
    if err != nil {
        if IsErrCommentNotExist(err) {
            return nil
        }
        return err
    }

    // Directly deletes without checking repository ownership
    sess := x.NewSession()
    defer sess.Close()
    if err = sess.Begin(); err != nil {
        return err
    }

    if _, err = sess.ID(comment.ID).Delete(new(Comment)); err != nil {
        // ...
    }
    // ...
}

Proof of Concept

Prerequisites

Two users: Alice (attacker) and Bob (victim)
Alice is admin of alice/attacker-repo
Bob has created an issue with a comment on bob/victim-repo
Attacker needs to obtain the comment ID from victim's repository (e.g., ID: 42)

HTTP Request

POST /alice/attacker-repo/issues/comments/42/delete HTTP/1.1
Host: gogs.example.com
Cookie: i_like_gogs=<alice_session_token>

Technologies

Gogs GogsGogs.Io Gogs

Weaknesses

CWE-639

MITRE ATT&CK

Inferred

Where this vulnerability fits in an attack

ReconImpact

Initial Access

T1190Exploit Public-Facing Application

References

Potentially impacted assets

See if this affects your attack surface

Latest trending attack

Criticalyesterday

Google Brotli decoder - Remote Code Execution via compressed requests (Exploitation Check)

This control is the second step of the Patrowl response to CVE-2026-111497 (Node2Shell). It complements the first control of 22 October 2026, which focused on the Node.js runtime, and does not replace it. Why a second control CVE-2026-111497 is an out-of-bounds write in the Google Brotli decoder, the library that decompresses Brotli ("br") data. It was first published as a Node.js vulnerability, because Node.js bundles this decoder. Later publications showed that the flaw is in the library itself. Every product that embeds an affected version of the decoder is concerned, whatever its language or vendor. A public proof of concept demonstrates code execution. Any server that decompresses request bodies sent with "Content-Encoding: br" exposes the decoder to unauthenticated attackers. Known cases include Express 5 and NestJS 11 on Node.js, Koa and Fastify setups, Bun, Envoy and Istio with request decompression enabled, and any application or reverse proxy that decodes Brotli request bodies with an affected library. The flaw also works in the other direction. A malicious server can compromise an unpatched client that decodes a Brotli response, for example Node.js fetch(), Python clients (requests, httpx, aiohttp, Scrapy) with the Brotli or brotlicffi package, or libcurl builds with Brotli support. What this control checks Patrowl sends small, valid Brotli-compressed requests to each asset and observes whether the server decodes them. The check does not depend on the technology: it detects the behaviour, whatever the stack behind it. These requests are what any legitimate client could send. They never reach the vulnerable code path and cannot affect the availability of the service. How to read the result Potentially impacted means the asset decodes Brotli request bodies: the attack surface is exposed. It does not confirm that the asset is vulnerable. The version of the Brotli decoder in use is not visible from the outside. This check covers applications that parse request bodies on their root path. A Not impacted result does not rule out exposure on other routes, nor on the client side. Checking the versions on the servers remains the only exhaustive verification. Affected and fixed versions Google Brotli 1.0.3 to 1.2.0 are affected, fixed in 1.0.10, 1.1.1 and 1.2.1. Fixed releases of the main products embedding it: Node.js 22.23.4, 24.22.1 and 26.12.1 (end-of-life lines 20.x and older and 25.x receive no fix), Bun 1.4.4, Envoy 1.37.8, 1.38.6, 1.39.3 and 1.40.0, Istio 1.29.9, 1.30.6 and 1.31.2, Python Brotli 1.2.1 and brotlicffi 1.2.1.0. Products that link against the system library depend on the Brotli package of the Linux distribution. Recommendations Update every component that embeds the Brotli decoder (only real fix). Start with the assets flagged by this control. Restart the processes after the update. Rebuild containers, single-executable applications and appliances that bundle an affected runtime or library. Reduce the exposure until the update is deployed. Reject requests with "Content-Encoding: br" at the reverse proxy, load balancer or WAF, case-insensitively and including lists such as "gzip, br". On Envoy and Istio, disable request decompression for Brotli. Review outbound calls. List the features that fetch content from servers you do not control, and patch the services that host them first.