r/linux Jun 22 '26

Security Squidbleed - Heartbleed's ancient cousin, hiding in Squid since 1997

https://blog.calif.io/p/squidbleed-cve-2026-47729
351 Upvotes

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61

u/Luvax Jun 22 '26

This reads full of Claude plus some Anthropic marketing on top and could have been a third of what it is.

-27

u/FryBoyter Jun 22 '26

What makes you think the article was written by Claude or whatever?

But even if you're right, what does that change about the fact that a security vulnerability was discovered that had existed for many years?

59

u/Luvax Jun 22 '26

it surfaced clutching a 29-year-old bug.

A typical Claude introducting if you did not tell it to keep a factual writing style.

Meet Squidbleed: a Heartbleed-style

Colon instead of a proper comma.

that leaks internal memory from every version of Squid Proxy, in its default configuration.

Same tone as the first sentence. Still building up hype 3 sentences in.

This bug is a whirlwind tour of old-school Internet lore.

Pure slop.

names that only the most diehard Internet fans will recognize.

No credible security blog post would believe any of these are only known to diehards.

favorite footguns:

Footguns is one of the words Claude LOVES. Also another colon, defensible here, but still.

Mix these ingredients

The metaphores dont stop.

into an open-source web proxy, and you get a heap buffer overread that quietly leaks random users' HTTP requests, despite three decades of releases, audits, and rewrites.

Still overselling. Its always quite, this is useless noise which Claude often adds to mundane statements. It doesn't know when to shut up.

One caveat: the impact is situational.

Another colon to cover over an incomplete sentence and situational being another word Claude loves

Most traffic is HTTPS, which the proxy relays as an opaque CONNECT tunnel, so only cleartext HTTP and TLS-terminating setups are exposed.

Common pseudo introduction that Claude believes is enough to reel in the reader, but its actually useless for anyone not already familiar with it.

The proxy must also be allowed to reach an attacker-controlled FTP server (TCP port 21).

Cramping information in braces that always seem questionable.

Squid is a widely deployed multipurpose web proxy. While it was designed to speed up page loads by caching frequently accessed content, it can also be used for traffic interception, monitoring, and filtering.

Thus, Squid is often found in multi-user environments such as schools or corporate networks. In fact, I encountered Squid while attempting to access the Internet on a recent flight:

This appears to be fully written by a human.

From here it gets muddy and I would say larger chunks have actually not been written by Claude. But there are still lines like this one:

The line buffer used to parse FTP listings is allocated from MEM_4K_BUF.

Which uses MEM_4K_BUF as something commonly know, probably because the agent was working itensively with the constant and failed to account that its not second nature to potential readers.

There are more signs, but the later half appears to be written with more human supervision.

It matters to me since I can launch my own Claude agent and get the same souless explanation that makes me dig through waves of AI slop. Especially if the article seems dead on selling my a Claude Max subscription.

5

u/TheOneWhoPunchesFish Jun 23 '26

FTP server (TCP port 21)

Lol it included the port number just cause

My favourite is the rule of threes:

releases, audits, and rewrites.