# CVE-2025-52494: CVE-2025-52494

Status: published. Published: 2025-09-03. Updated: 2026-11-07.

Adacore Ada Web Server (AWS) before 25.2 is vulnerable to a denial-of-service (DoS) condition due to improper handling of SSL handshakes during connection initialization. When a client initiates an HTTPS connection, the server performs the SSL handshake before assigning the connection to a processing slot. However, there is no specific timeout set for this phase, and the server uses the default socket timeout, which is effectively infinite. An attacker can exploit this by sending a malformed TLS ClientHello message with incorrect length values. This causes the server to wait indefinitely for data that never arrives, blocking the worker thread (Line) handling the connection. By opening multiple such connections, up to the server's maximum limit, the attacker can exhaust all available working threads, preventing the server from handling new, legitimate requests.

## Remediation

No remediation reported in collected sources

## Affected products and versions

- adacore / ada_web_server: < 26.0 (affected, custom). Source: NVD

## NVD configuration conditions

Affected CPE matches depend on the following AND/OR and negation conditions:

```json
[
  {
    "negate": false,
    "nodes": [
      {
        "cpeMatch": [
          {
            "criteria": "cpe:2.3:a:adacore:ada_web_server:*:*:*:*:*:*:*:*",
            "versionEndExcluding": "26.0",
            "vulnerable": true
          }
        ],
        "negate": false,
        "operator": "OR"
      }
    ],
    "operator": "OR"
  }
]
```

## Severity and prioritization

- CVSS 3.1: 7.5 (high); CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H; source: NVD: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- CISA KEV: No listing in collected sources

- EPSS: Not available

- SSVC: exploitation none; automatable yes; technical impact partial; source NVD SSVC: 134c704f-9b21-4f2e-91b3-4a467353bcc0

- Weaknesses: CWE-400

## Exploit evidence

No exploit evidence in collected sources. This is not proof of no exploitation.

## References

- https://adacore.com/ (cve@mitre.org; Product)

- https://docs.adacore.com/corp/security-advisories/SEC.AWS-0095-v1.pdf (cve@mitre.org; Technical Description, Vendor Advisory)

## Provenance

- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-52494; retrieved 2026-11-07; source updated 2026-11-07

Revision: 4f9258e503bcbc7c0a632418009851bf3c0b2975cb77872cf5a3c066fb042135

Canonical: https://y2.dev/cve/CVE-2025-52494

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