Vulnerability in jsx-slack (CVE-2021-43838)
Summary
Vulnerability in jsx-slack (CVE-2021-43838). Risk of unauthorized operations or information disclosure. Mitigation: upgrade to 4.5.1 or later.
Original description
The description as published by the source.
jsx-slack is a library for building JSON objects for Slack Block Kit surfaces from JSX. In versions prior to 4.5.1 users are vulnerable to a regular expression denial-of-service (ReDoS) attack. If attacker can put a lot of JSX elements into `` tag, an internal regular expression for escaping characters may consume an excessive amount of computing resources. jsx-slack v4.5.1 has patched to a regex for escaping blockquote characters. Users are advised to upgrade as soon as possible.
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-2021-43838 has been found in jsx-slack.
Risk of unauthorized operations or information disclosure.
What to do: upgrade jsx-slack to 4.5.1 or later.
If unsure, ask your IT team or search "jsx-slack CVE-2021-43838" on the vendor's site.
CVE-2021-43838 (jsx-slack) — CWE-1333
Attack vector: remote (network-reachable) / unauthenticated / no user interaction
Patched: 4.5.1 — 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.
A vulnerability (CWE-1333) exists in jsx-slack.
Check the vendor advisory for the affected versions of jsx-slack.
Severity: ?. Risk of unauthorized operations or information disclosure.
Update to 4.5.1.
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 'jsx-slack' . 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
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1Identify exposure identify
grep -r 'jsx-slack' . | 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
jsx-slack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 jsx-slack to 4.5.1ステージング環境で 4.5.1 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
- patch github.com
- patch github.com
- web github.com