GHSA-4J89-2C4F-44C6

Vulnerability from github – Published: 2026-06-22 23:58 – Updated: 2026-06-22 23:58
VLAI
Summary
Gogs has DoS in rendering issue index pattern
Details

Summary

Special template of issue index pattern may cause panic.

Details

in internal/markup/markup.go

link = fmt.Sprintf(`<a href="%s">%s</a>`, com.Expand(metas["format"], metas), m)

Issue index pattern is rendered to link with com.Expand.

However, com.Expand is not safe.

i = strings.Index(template, "}")
if s, ok := match[template[:i]]; ok {

when { is found but } not found, i comes to 1, template[:-1] will be called, and then panicked

image

finally, all pages than contains issue index are unavailable.

PoC

  1. set issue index pattern as follow

image

  1. add a commit which point to an issue in its msg

image

using #1 above

Impact

DoS that cause part of pages of the specify repo unavailable.

Severity
3.5 (Low)
CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L
Show details on source website
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{
  "affected": [
    {
      "database_specific": {
        "last_known_affected_version_range": "\u003c= 0.14.2"
      },
      "package": {
        "ecosystem": "Go",
        "name": "gogs.io/gogs"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0"
            },
            {
              "fixed": "0.14.3"
            }
          ],
          "type": "ECOSYSTEM"
        }
      ]
    }
  ],
  "aliases": [
    "CVE-2026-52796"
  ],
  "database_specific": {
    "cwe_ids": [
      "CWE-1336"
    ],
    "github_reviewed": true,
    "github_reviewed_at": "2026-06-22T23:58:17Z",
    "nvd_published_at": null,
    "severity": "LOW"
  },
  "details": "### Summary\nSpecial template of issue index pattern may cause panic.\n\n### Details\n\nin internal/markup/markup.go\n\n```go\nlink = fmt.Sprintf(`\u003ca href=\"%s\"\u003e%s\u003c/a\u003e`, com.Expand(metas[\"format\"], metas), m)\n```\n\nIssue index pattern is rendered to link with `com.Expand`.\n\nHowever, `com.Expand` is not safe.\n\n```go\ni = strings.Index(template, \"}\")\nif s, ok := match[template[:i]]; ok {\n```\n\nwhen `{` is found but `}` not found, i comes to 1, template[:-1] will be called, and then panicked\n\n![image](https://user-images.githubusercontent.com/38121125/285883766-64873c44-d325-44ce-96a8-badbaadab178.png)\n\nfinally, all pages than contains issue index are unavailable.\n\n### PoC\n\n1. set issue index pattern as follow\n\n![image](https://user-images.githubusercontent.com/38121125/285878157-c5fe848e-0fbd-4fdb-92d4-5eb01df2b8ca.png)\n\n2. add a commit which point to an issue in its msg\n\n![image](https://user-images.githubusercontent.com/38121125/285879545-bc360503-49b9-453f-aa24-9a5c5a45cf10.png)\n\nusing `#1` above\n\n### Impact\n\nDoS that cause part of pages of the specify repo unavailable.",
  "id": "GHSA-4j89-2c4f-44c6",
  "modified": "2026-06-22T23:58:17Z",
  "published": "2026-06-22T23:58:17Z",
  "references": [
    {
      "type": "WEB",
      "url": "https://github.com/gogs/gogs/security/advisories/GHSA-4j89-2c4f-44c6"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gogs/gogs/pull/8312"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gogs/gogs/commit/0529d95fc39f2b6d2997b19a2a12e24522684722"
    },
    {
      "type": "PACKAGE",
      "url": "https://github.com/gogs/gogs"
    },
    {
      "type": "WEB",
      "url": "https://github.com/gogs/gogs/releases/tag/v0.14.3"
    }
  ],
  "schema_version": "1.4.0",
  "severity": [
    {
      "score": "CVSS:3.1/AV:N/AC:L/PR:L/UI:R/S:U/C:N/I:N/A:L",
      "type": "CVSS_V3"
    }
  ],
  "summary": "Gogs has DoS in rendering issue index pattern"
}


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