[KEV] Out-of-Bounds Write in Apple iOS (CVE-2021-30761)
Summary
Out-of-bounds write in Apple iOS (CVE-2021-30761). Risk of unauthorized operations or information disclosure. Listed in CISA KEV — actively exploited.
Original description
The description as published by the source.
Apple iOS WebKit contains a memory corruption vulnerability that leads to code execution when processing maliciously crafted web content. This vulnerability could impact HTML parsers that use WebKit, including but not limited to Apple Safari and non-Apple products which rely on WebKit for HTML processing.
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-2021-30761 has been found in Apple iOS.
Risk of unauthorized operations or information disclosure.
Note: CISA has officially confirmed this is actively exploited in the wild. Treat it with elevated urgency.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Apple iOS CVE-2021-30761" on the vendor's site.
CVE-2021-30761 (Apple iOS) — CWE-787
Listed in CISA KEV — actively exploited, treat as top priority.
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.
Out-of-bounds write (CWE-787) exists in Apple iOS.
Check the vendor advisory for the affected versions of Apple iOS.
Severity: High. Risk of unauthorized operations or information disclosure. Listed in CISA KEV — actively exploited in the wild, treat as top priority.
Update to the patched release per vendor advisory.
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 'iOS' . 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 'iOS' . | 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
iOSを grep し、稼働しているサービス・バージョンを把握する。 -
2Consider incident declaration escalate
Notify SOC / on-callCISA KEV登録済 = 実環境で悪用が観測されている。侵入の兆候があればインシデント対応宣言、無くてもパッチ適用までWAF強化を最優先で。
-
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。
References
- advisory NVD