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hubie [soylentnews.org] writes:

GNU inetutils Telnetd CVE-2026-32746 Pre-Auth RCE [watchtowr.com]:

A long, long time ago, in a land free of binary exploit mitigations, when Unix still roamed the Earth, there lived a pre-authentication Telnetd vulnerability.

In fact, this vulnerability was born so long ago (way back in 1994) that it may even be older than you. To put the timespan in perspective: it came into existence the same year the seminal movie Hackers was released.

That was so long ago that RISC was still a distant dream.

Come to think of it, maybe it was even the product of Zero Cool himself?

Anyway. Recently, this vulnerability was brutally put to rest.

[...] CVE-2026-32746, discovered by the DREAM Security Research Team, is a BSS-based buffer overflow that allows an attacker to corrupt roughly 400 bytes of adjacent variables.

It resides in the LINEMODE SLC (Set Linemode Characters) negotiation handler. While strictly speaking it affects 'just' GNU inetutils, most vendors have based their Telnetd implementations on the same code, making the blast radius vast and somewhat difficult to estimate. It definitely includes all the major Linux distributions (we checked).

With a vulnerability like this, we expected the Internet to explode with excitement - yet it's been almost a week now with no good analysis. We thought we might as well publish where we got to.

We'll go through a few things - how we isolated the vulnerability, what it enables attackers to do (and under what circumstances), and we'll talk about why this particular vulnerability is more of a Pandora's box to exploit than you might think.

Original Submission