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wolfSSH ECDSA host key curve not validated against negotiated algorithm

Type: advisorySource: Official CVE List1 source record

wolfSSH does not validate that the ECDSA curve identifier in a KEXDH_REPLY host key blob matches the algorithm negotiated during key exchange. In ParseECCPubKey() (src/internal.c), the blob's algorithm string is used to derive the curve via NameToId/wcPrimeForId without checking against the negotiated ssh->handshake->pubKeyId, and the RFC 5656 curve identifier string is discarded via GetSkip() rather than compared. An active network man-in-the-middle attacker can substitute a host key blob containing a different ECDSA curve, causing the client to import the key on the wrong curve. Because the attacker controls the private key for the substituted curve, signature verification passes. Exploitation requires an active MitM position and a lax public key check callback (e.g., TOFU, algorithm-name-only check, or fingerprint match against the parsed key).

Announced Source revision 1
Original source ↗

CVE-2026-16516

Primary source · Revision 1

Imported from structured advisory data. Source references identify upstream records or fields; verify affected versions and your deployed configuration.

Security context

Source reference: cve:CVE-2026-16516

wolfSSH

Source reference: /containers/cna/affected/0/product

Affected versions
Not stated in this record
Fixed versions
Not stated in this record
Prerequisites
Not stated in this record

Structured affected-version data

Original package identities and version rules from this source.

[
  {
    "repo": "https://github.com/wolfSSL/wolfssh",
    "vendor": "wolfSSL Inc.",
    "product": "wolfSSH",
    "versions": [
      {
        "status": "affected",
        "changes": [
          {
            "at": "1.6.0",
            "status": "unaffected"
          }
        ],
        "version": "0",
        "versionType": "semver",
        "lessThanOrEqual": "1.5.0"
      }
    ],
    "programFiles": [
      "src/internal.c"
    ],
    "defaultStatus": "unaffected"
  }
]
Related CVEs
CVE-2026-16516

Source reference: /cveMetadata/cveId

Publisher severity

critical

Source reference: /containers/cna/metrics

Event
#11847 · Revision 1
Added to Heist Feed
Publisher date
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