RUSTSEC-2026-0264 `proc-macro-en` was removed from crates.io due to malicious code
Malicious Rust crate proc-macro-en executes arbitrary code during build, requiring developers to remove it from dependencies.
- Exploited in the wild
- Not known
- Login needed
- Not needed
- Attackable
- Over the internet
- Victim action needed
- Not needed
- Fix
- None listed
What is RUSTSEC-2026-0264?
RUSTSEC-2026-0264 is a vulnerability in proc-macro-en, published on 20 Aug 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.
Official description
We identified that proc-macro-en contained the same build script as
proc-macro1 and it was part of the same supply chain attack.
This crate had one single version published at 2026-08-20. The crate was removed from crates.io and related user account was locked.
This crate was used as part of a malware campaign targeted at users of
arrayref, which was downloaded 2,285 times before being removed; see
the arrayref advisory for more detail.
Which versions are affected by RUSTSEC-2026-0264?
1 open source package ship an affected version, including proc-macro-en.
| Package | Affected | Fixed in |
|---|---|---|
proc-macro-en crates.io | From 0.0.0-0 | None |
How do I fix RUSTSEC-2026-0264?
No fix has been published for RUSTSEC-2026-0264 yet. Limit exposure of the affected software until one is available.
Is RUSTSEC-2026-0264 being exploited?
There is no known exploitation of RUSTSEC-2026-0264 in the wild and no public exploit code.