OpenSSL: Stack buffer overflow in CMS AuthEnvelopedData parsing

I'd encourage folks to read the recently-published statement [1] about the state of OpenSSL from Python's cryptography project.

[1]: https://news.ycombinator.com/item?id=46624352

2026 and we still have bugs from copying unbounded user input into fixed size stack buffers in security critical code. Oh well, maybe we'll fix it in the next 30 years instead.

Looks like Debian and some other distros are still on the vulnerable 3.5.4. Why did Openssl publish before the distros rolled to the fixed version?

Has anyone built OpenSSL with -fbounds-safety?

Can someone translate

"Applications and services that parse untrusted CMS or PKCS#7 content using AEAD ciphers (e.g., S/MIME AuthEnvelopedData with AES-GCM) are vulnerable"

to human?

Is this really exploitable? Is stack smashing really still a thing on any modern platform?

Very strange, as I type this both Bullseye and Bookworm are marked as fixed but Trixie isn't yet:

https://security-tracker.debian.org/tracker/CVE-2025-11187

Another "fix" in the long line of OpenSSL "fixes" that includes no changes to tests and therefore can't really be said to fix anything. Professional standards of software development are simply absent in the project, and apparently it cannot be reformed, because we've all been waiting a long time for OpenSSL to get its act together.

Please use Rust.