MSG_PEEK is pretty common, CVE-2016-10229 is worse than you think April 13, 2017 on Drew DeVault's blog

I heard about CVE-2016-10229 earlier today. In a nutshell, it allows for arbitrary code execution via UDP traffic if userspace programs are using MSG_PEEK in their recv calls. I quickly updated my kernels and rebooted any boxes where necessary, but when I read the discussions on this matter I saw people downplaying this issue by claiming MSG_PEEK is an obscure feature.

I don’t want to be a fear monger and I’m by no means a security expert but I suspect that this is a deeply incorrect conclusion. If I understand this vulnerability right you need to drop everything and update any servers running a kernel <4.5 immediately. MSG_PEEK allows a programmer using UDP to read from the kernel’s UDP buffer without consuming the data (so subsequent reads will continue to read the same data). This immediately sounds to me like a pretty useful feature that a lot of software might use, not an obscure one.

I did quick search for software where MSG_PEEK appears in the source code somewhere. This does not necessarily mean that it’s exploitable, but should certainly raise red flags. Here’s a list of some notable software I found:

I also found a few things like programming languages and networking libraries that you might expect to have MSG_PEEK if only to provide that functionality to programmers leveraging them. I didn’t investigate too deeply into whether or not that was the case or if this software is using the feature in a less apparent way, but in this category I found Python, Ruby, Node.js, smalltalk, octave, libnl, and socat. I used searchcode.com to find these - here’s the full search results.

Again, I’m not a security expert, but I’m definitely spooked enough to update my shit and I suggest you do so as well. Red Hat, Debian, and Ubuntu are all unaffected because of the kernel they ship. Note, however, that many cloud providers do not let you choose your own kernel. This could mean that you are affected even if you’re running a distribution like Debian. Double check it - use uname -r and update+reboot if necessary.

Articles from blogs I read Generated by openring

hare-update assists in addressing breaking changes in your code

We’re working on a new tool to release along the next upcoming stable release of Hare (likely Hare 0.25.2, or 0.25.3, following our release policy) – hare-update. The coming Hare release includes a number of small breaking changes, as per usual during Hare’s…

via Blogs on The Hare programming language June 11, 2025

Open Source: Deceptive Power or Collective Governance?

In October 2024, it emerged that WordPress co-founder Matt Mullenweg has extensive power over the entire WordPress ecosystem, which 43% of all websites on the internet run on. When he exercised this power by seizing control of code that runs on tens of thou…

via Vlad's Website June 6, 2025

Summary of changes for May 2025

Hey everyone!This is the list of all the changes we've done to our projects during the month of May. 100r.co, updated Oquonie and water. Modal, the interpreter was ported to Uxn! Uxntal, the documentation has been completely redone! Hakum, added p…

via Hundred Rabbits May 31, 2025