rustsec-2026-0265
Vulnerability from osv_rustsec
Published
2026-08-20 12:00
Modified
2026-08-21 06:28
Summary
`proc-macro1` was removed from crates.io due to malicious code
Details

It was reported proc-macro1 contained a build script that would download a malicious payload.

This crate had two versions, both published on 2026-08-20. The crate was removed from crates.io and related user accounts were 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.

Thanks to the Research Team at Nextron Systems GmbH for reporting this to the Rust security response working group, and thanks to Emily Albini for coordinating with the crates.io and infra-admin teams.

References
To clipboard 

{
  "affected": [
    {
      "database_specific": {
        "categories": [
          "malicious"
        ],
        "cvss": null,
        "informational": null
      },
      "ecosystem_specific": {
        "affected_functions": null,
        "affects": {
          "arch": [],
          "functions": [],
          "os": []
        }
      },
      "package": {
        "ecosystem": "crates.io",
        "name": "proc-macro1",
        "purl": "pkg:cargo/proc-macro1"
      },
      "ranges": [
        {
          "events": [
            {
              "introduced": "0.0.0-0"
            }
          ],
          "type": "SEMVER"
        }
      ],
      "versions": []
    }
  ],
  "aliases": [],
  "database_specific": {
    "license": "CC0-1.0"
  },
  "details": "It was reported `proc-macro1` contained a build script that would download a\nmalicious payload.\n\nThis crate had two versions, both published on 2026-08-20. The crate was\nremoved from crates.io and related user accounts were locked.\n\nThis crate was used as part of a malware campaign targeted at users of\n`arrayref`, which was downloaded 2,285 times before being removed; see\n[the `arrayref` advisory][arrayref-advisory] for more detail.\n\nThanks to the Research Team at Nextron Systems GmbH for reporting this to the\nRust security response working group, and thanks to Emily Albini for coordinating\nwith the crates.io and infra-admin teams.\n\n[arrayref-advisory]: https://rustsec.org/advisories/RUSTSEC-2026-0260.html",
  "id": "RUSTSEC-2026-0265",
  "modified": "2026-08-21T06:28:40Z",
  "published": "2026-08-20T12:00:00Z",
  "references": [
    {
      "type": "PACKAGE",
      "url": "https://crates.io/crates/proc-macro1"
    },
    {
      "type": "ADVISORY",
      "url": "https://rustsec.org/advisories/RUSTSEC-2026-0265.html"
    },
    {
      "type": "WEB",
      "url": "https://blog.rust-lang.org/2026/08/20/supply-chain-attack-on-arrayref"
    }
  ],
  "related": [],
  "severity": [],
  "summary": "`proc-macro1` was removed from crates.io due to malicious code"
}



Log in or create an account to share your comment.




Tags
Taxonomy of the tags.





Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

Author Source Type Date Other

Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.