# CASCA evidence receipt — CVE-2024-20481

- Generation: `gen-56ccdaf914f7b4be95b689ccae7dc20d`
- As known: 2026-07-19T05:00:42+00:00
- Comparison: first_public_core_generation
- Score policy: public-priority-v1.0.1
- Conflict: not observed in this generation

## Source assertions

- **CISA-ADP** (independent_enrichment): container — CISA ADP Vulnrichment
  - Observed: 2026-07-19T04:27:06.398189+00:00
  - Citation: https://www.cve.org/CVERecord?id=CVE-2024-20481
- **cisco** (original_assertion): container — A vulnerability in the Remote Access VPN (RAVPN) service of Cisco Adaptive Security Appliance (ASA) Software and Cisco Firepower Threat Defense (FTD) Software could allow an unauthenticated, remote attacker to cause a denial of service (DoS) of the RAVPN service.

 This vulnerability is due to resource exhaustion. An attacker could exploit this vulnerability by sending a large number of VPN authentication requests to an affected device. A successful exploit could allow the attacker to exhaust resources, resulting in a DoS of the RAVPN service on the affected device. Depending on the impact of the attack, a reload of the device may be required to restore the RAVPN service. Services that are not related to VPN are not affected.

 Cisco Talos discussed these attacks in the blog post Large-scale brute-force activity targeting VPNs, SSH services with commonly used login credentials.
  - Observed: 2026-07-19T04:27:06.398189+00:00
  - Citation: https://www.cve.org/CVERecord?id=CVE-2024-20481
- **CISA KEV** (original_assertion): observed_exploitation — Cisco ASA and FTD Denial-of-Service Vulnerability
  - Observed: 2026-07-19T04:54:04.25158+00:00
  - Citation: https://www.cisa.gov/known-exploited-vulnerabilities-catalog
- **FIRST EPSS** (original_assertion): model_probability — Probability 0.159530000000; percentile 0.965360000000
  - Observed: 2026-07-19T04:54:35.756809+00:00
  - Citation: https://www.first.org/epss/data_stats.html

## CVSS assessments

- **nvd@nist.gov** (Primary, CVSS 3.1): 5.8 — score eligible
  - Evidence class: nvd_enrichment_exact; source rank: 0
  - Validation: valid_match
  - Vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L`
- **psirt@cisco.com** (Secondary, CVSS 3.1): 5.8 — score eligible
  - Evidence class: exact_record_cna; source rank: 1
  - Validation: valid_match
  - Vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L`
- **cisco** (unknown, CVSS 3.1): 5.8 — display only
  - Evidence class: direct_cve_record_display_only; source rank: not applicable
  - Validation: display-only direct record assessment
  - Vector: `CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:C/C:N/I:N/A:L`

## Limitations and unknowns

- KEV membership is authoritative for the catalog, not proof of exposure in any environment.
- EPSS is a dated model probability and not an individual-environment prediction.
- Affected or fixed status applies only to the exact cited product and version scope; unresolved scope remains unknown.
- NVD-carried upstream facts remain derivative and are not independent corroboration.
- Only NVD metrics validated under the generation-bound calculator are Public Priority eligible; direct CVE record metrics remain display-only.
- NVD CVSS source eligibility is closed: NVD-authored, exact record-source, or registered same-CVE container origin; unmapped sources remain display-only.
- Factor D is unknown in Public Core because no accepted canonical mapping-obligation ledger is present.
- Core replay supports the active and immediately prior generation; retrospective valid-at replay is deferred.

Generated from CASCA normalized evidence. This receipt is not proof that an asset is affected, unaffected, safe, or fixed.