CPanel and WHM Authentication Bypass – CVE-2026-41940

superasn•about 3 hours ago

Everytime I read one of these it always boils down to the same thing..Don't solve solved problems. And the best code in this case is code you didn't write as PHP's session handler is battle-tested but every line you write to roll your own is a line you have to secure, maintain, and eventually patch at 2am when someone finds the bug.

Session handling, auth, crypto, password hashing etc - all these are the exact areas where you should be the most allergic to rolling your own. Not because you're not smart enough, but because a simple bug like sanitizing in the wrong place and the failure is catastrophic like in this instance.

Use boring, proven, widely-audited solutions. Save your creativity for the actual problem you're solving.

bananamogul•about 2 hours ago

“And the best code in this case is code you didn't write as PHP's session handler is battle-tested”

cPanel is written in perl.

superasn•about 2 hours ago

Oh you're right to push back. I just love saying this nowadays :P Anyway, I haven't used these languages in a long time but the code looked like php to me, though I did notice the .pm file extension and wondered where I've seen it before.

ryandrake•about 2 hours ago

I don't even know why you'd want to re-implement this stuff, too. It's not exciting or sexy work. It's like time parsing, time zone handling, leap years... Why would you want to inflict that on yourself? You will 100% not handle every edge case, and you will 100% get time and time zone handling bugs.

shawnz•about 2 hours ago

cPanel is 30 years old, are you saying it's not battle tested, boring, proven, and widely audited?

In fact PHP is only a few months older than it.

yabones•about 3 hours ago

Oooooh that's really bad. Wordpress on Cpanel sites is like the Dark Matter of the internet, it's everywhere and you don't see it until something bad happens. Libations for the sysadmins patching & cleaning up this mess.

xtracto•about 1 hour ago

At the rate we are going, we will all go back to publish HTML website like in Geocities times.

anakaine•about 1 hour ago

Conceptually, static sites are probably not too far off this.

amluto•about 1 hour ago

I like how the vulnerability is in the path that (a) attempts to write the password in reversibly encrypted form to disk [0] and (b) has a weird fallback path that writes it in clear text. Sigh.

[0] cPabel seems to be from 1996. We’ve known this is a mistake since before 1996.

debo_•about 3 hours ago

I wonder how much of the web still runs on perl. I miss it sometimes.

mushufasa•about 3 hours ago

I used to help nonprofits and small businesses build websites. Process always went like 1. buy domain, 2. buy a shared hosting provider that one-click-installs Wordpress, 3. use a theme to begin editing the website. Often, I would also use the email included with that hosting provider for the firm.

ALL of that goes through cpanel, for every shared hosting provider I can ever remember using. Even if the stuff happening on those servers didn't use perl, cpanel itself -- the admin of everything provided for that domain by the hosting provider -- it's a huge surface area.

Loudergood•about 3 hours ago

That's gonna pair really well with this.

https://copy.fail

yunnpp•about 2 hours ago

Why? This one gives you a root shell directly, no need for an LPE.

whalesalad•about 2 hours ago

> this vulnerability affects - and we cannot stress this enough - all currently supported versions of cPanel & WHM

yikes. https://www.shodan.io/search?query=basic+realm%3D%22cPanel%2...

ls612•about 2 hours ago

Something that is starting to concern me with the flood of cyber chaos in the past couple of months is my homelab. Currently I do not have it set up to be accessible outside the local network and then add it and all my other devices to my tailnet to facilitate remote access (via an exit node on my local network). On top of that TrueNAS doesn't seem to have the best update cadence so I'm worried about having a system with known vulnerabilities only protected by not being accessible remotely in theory.

ChrisArchitect•about 2 hours ago

Earlier: https://news.ycombinator.com/item?id=47967974

mushufasa•about 3 hours ago

Oh dear.

0xbadcafebee•about 3 hours ago

Y'know what would help protect those internet buildings from falling on people? A software building code

CPanel and WHM Authentication Bypass – CVE-2026-41940

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