UnratedFix available

Panic due to improper UTF-8 indexing

Type: advisorySources: OSV

When parsing untrusted rulex expressions, rulex may panic, possibly enabling a Denial of Service attack. This happens when the expression contains a multi- byte UTF-8 code point in a string literal or after a backslash, because rulex tries to slice into the code point and panics as a result. The flaw was corrected in commits `fac6d58b25` and `330b3534e7` by using `len_utf8()` to derive character width in bytes instead of assuming ASCII encoding of 1 byte per char.

Products: rulex
Affected versions: Not specified
Fixed versions: 0.4.3
CVEs: CVE-2022-31100
Confirmed fixed CVEs: Not specified
Updated in this feed: 30 Oct 2026, 08:42 UTC · Revision 1

Source evidence

Panic due to improper UTF-8 indexing

core-osv · Original source

Published 21 May 2022, 12:00 UTC

osv:RUSTSEC-2022-0031

rulex

Fixed versions: 0.4.3

Complete source record

{
  "id": "b77d3658bb6ffe8a2325ca29f9493491838abc9b797ed4f740b9d31b5c0a9f4f",
  "url": "https://osv.dev/vulnerability/RUSTSEC-2022-0031",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "Panic due to improper UTF-8 indexing",
    "summary": "When parsing untrusted rulex expressions, rulex may panic, possibly enabling a Denial of Service attack. This happens when the expression contains a multi- byte UTF-8 code point in a string literal or after a backslash, because rulex tries to slice into the code point and panics as a result. The flaw was corrected in commits `fac6d58b25` and `330b3534e7` by using `len_utf8()` to derive character width in bytes instead of assuming ASCII encoding of 1 byte per char.",
    "evidence": "osv:RUSTSEC-2022-0031",
    "products": [
      {
        "name": {
          "value": "rulex",
          "evidence": "/affected/0/package/name"
        },
        "prerequisites": [],
        "fixed_versions": [
          {
            "value": "0.4.3",
            "evidence": "/affected/0/ranges"
          }
        ],
        "affected_versions": []
      }
    ],
    "severity": "unknown",
    "structured": {
      "id": "RUSTSEC-2022-0031",
      "aliases": [
        "CVE-2022-31100",
        "GHSA-8v9w-p43c-r885",
        "RUSTSEC-2022-0031"
      ],
      "affected": [
        {
          "ranges": [
            {
              "type": "SEMVER",
              "events": [
                {
                  "introduced": "0.0.0-0"
                },
                {
                  "fixed": "0.4.3"
                }
              ]
            }
          ],
          "package": {
            "name": "rulex",
            "purl": "pkg:cargo/rulex",
            "ecosystem": "crates.io"
          },
          "database_specific": {
            "cvss": null,
            "source": "https://github.com/rustsec/advisory-db/blob/osv/crates/RUSTSEC-2022-0031.json",
            "categories": [
              "denial-of-service"
            ],
            "informational": null
          },
          "ecosystem_specific": {
            "affects": {
              "os": [],
              "arch": [],
              "functions": []
            },
            "affected_functions": null
          }
        }
      ],
      "modified": "2026-10-12T18:00:05.115301404Z",
      "provider": "osv",
      "references": [
        "https://crates.io/crates/rulex",
        "https://rustsec.org/advisories/RUSTSEC-2022-0031.html",
        "https://github.com/rulex-rs/rulex/commit/fac6d58b25c6f9f8c0a6cdc4dec75b37b219f1d6"
      ],
      "provider_metadata": {
        "license": "CC0-1.0"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2022-31100",
        "evidence": "/aliases"
      }
    ],
    "security_relevant": true,
    "severity_evidence": null
  },
  "source_id": "core-osv",
  "document_id": 306348,
  "published_at": "2022-05-21T12:00:00+00:00"
}