AshAi tool loop never terminates when all tool calls are filtered out, enabling denial of service

{
  "id": "b46619b9e3415b910a064a93260191d263092491ad33c53047938e2ca603baa9",
  "url": "https://osv.dev/vulnerability/CVE-2026-82579",
  "method": "structured",
  "payload": {
    "kind": "advisory",
    "title": "AshAi tool loop never terminates when all tool calls are filtered out, enabling denial of service",
    "summary": "Loop with Unreachable Exit Condition (Infinite Loop) vulnerability in ash-project ash_ai allows an attacker who can influence a model's output to hang the tool loop and drive unbounded, repeated model requests. AshAi.ToolLoop classifies a model response of :tool_calls, then filters the calls through normalize_tool_calls/2 and unprocessed_tool_calls/2. Both can empty the list: a call missing a valid name, or one reusing a tool_call_id that already has a result in history, is dropped. With an empty list the loop appended nothing and recursed with a byte-identical message list, so the conversation never advanced and the same request was re-sent every iteration. Under the supported max_iterations: :infinity this never terminated; otherwise it exhausted the full budget. Prompt-injected content can make the model re-emit a spent tool_call_id. The fix treats an empty post-filter list as terminal. This issue affects ash_ai: from 0.6.0 before 1.0.0.",
    "evidence": "osv:CVE-2026-82579",
    "products": [],
    "severity": "medium",
    "structured": {
      "id": "CVE-2026-82579",
      "aliases": [
        "CVE-2026-82579",
        "EEF-CVE-2026-82579",
        "GHSA-rcx7-x2w5-mmc2"
      ],
      "metrics": [
        {
          "type": "CVSS_V4",
          "score": "CVSS:4.0/AV:N/AC:L/AT:P/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N"
        }
      ],
      "affected": [
        {
          "ranges": [
            {
              "repo": "https://github.com/ash-project/ash_ai",
              "type": "GIT",
              "events": [
                {
                  "introduced": "bc2122f78fca6c11d8ec2b9ac53148ec17476460"
                },
                {
                  "fixed": "53325fdab90afab628c6a53232ef2a9001580bd9"
                },
                {
                  "introduced": "c31e6f4b619d9e6f79088fdf4f2a3463941137a6"
                },
                {
                  "fixed": "f72b14744996e71df6d73480d617d963f340597b"
                }
              ],
              "database_specific": {
                "extracted_events": [
                  {
                    "range": [
                      {
                        "introduced": "bc2122f78fca6c11d8ec2b9ac53148ec17476460"
                      },
                      {
                        "fixed": "53325fdab90afab628c6a53232ef2a9001580bd9"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "introduced": "0.6.0"
                      },
                      {
                        "fixed": "1.0.0"
                      }
                    ],
                    "source": "AFFECTED_FIELD",
                    "strategy": "StandardRange"
                  },
                  {
                    "range": [
                      {
                        "fixed": "53325fdab90afab628c6a53232ef2a9001580bd9"
                      }
                    ],
                    "source": "REFERENCES_COMMIT"
                  }
                ]
              }
            }
          ],
          "versions": [
            "v0.8.2",
            "v0.8.1",
            "v0.8.0",
            "v0.7.3",
            "v0.7.2",
            "v0.7.1",
            "v0.7.0",
            "v0.6.1",
            "v0.6.0"
          ],
          "database_specific": {
            "source": "https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-82579.json"
          }
        }
      ],
      "modified": "2026-10-28T02:30:37.768572287Z",
      "provider": "osv",
      "references": [
        "https://cna.erlef.org/cves/CVE-2026-82579.html",
        "https://github.com",
        "https://osv.dev/vulnerability/EEF-CVE-2026-82579",
        "https://repo.hex.pm",
        "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82579.json",
        "https://github.com/ash-project/ash_ai/security/advisories/GHSA-rcx7-x2w5-mmc2",
        "https://nvd.nist.gov/vuln/detail/CVE-2026-82579",
        "https://github.com/ash-project/ash_ai/commit/53325fdab90afab628c6a53232ef2a9001580bd9",
        "https://github.com/ash-project/ash_ai"
      ],
      "provider_metadata": {
        "cwe_ids": [
          "CWE-835"
        ],
        "cna_assigner": "EEF",
        "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/82xxx/CVE-2026-82579.json"
      }
    },
    "related_cves": [
      {
        "value": "CVE-2026-82579",
        "evidence": "/id"
      }
    ],
    "security_relevant": true,
    "severity_evidence": "/severity/0/score"
  },
  "source_id": "core-osv",
  "document_id": 505277,
  "published_at": "2026-08-31T01:07:49.185+00:00"
}