CVE-2026-16516

CRITICALPre-NVD 9.09.0
EchelonGraph scoreLOW confidence

This critical-severity CVE scores 9.0 under a secondary CVSS source (NVD's own analysis pending). EPSS exploit-prediction score not yet available (the EPSS model rescores nightly; freshly-published CVEs typically appear within 48 hours). GitHub Security Advisory data not yet ingested — confidence will rise once GHSA publishes (typical lag: hours to days for open-source ecosystem CVEs; never for infrastructure-only CVEs).

Triggered by: NVD CVSS baseline
Sources: secondary
Trending — 3 sources updated this week
9.0EG
EchelonGraph verdictPlan a fixSerious severity, but no confirmed exploitation yet.
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: —CVSS: 9.0Exploit: None knownExposed services: Not assessed

A fix is available — apply it.

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).

CVSS v3
9.0
EG Score
9.0CRITICALlow confidence
EG Risk
41
EG Risk 41/100CISA SSVC

EG Risk is EchelonGraph's 0–100 priority score: it fuses intrinsic severity with real-world exploitation and automatability so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner. Distinct from the 0–10 EG Score (severity).

How it’s computed
Severity90% × 45%
Exploitation0% × 40%
Automatability0% × 15%
CISA SSVC: Track at every mission impact level.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
—
EPSS %ILE
—
KEV
Not listed

CISA SSVCTrack at every mission impact level.

A fix is available. Apply it within your standard update timelines.

Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Mission impact is CISA's Mission & Well-being decision point, and only you can judge it: high means the affected system is essential to your organisation's mission, or its compromise could cause irreversible harm to people. CISA's decision table

Published

October 7, 2026

Last Modified

October 7, 2026

Advisory Details (2)

Auto-updated Oct 7, 2026
Patch available. Sources: github_commit.
github_commit Patch Available

commit 31d13697a608 (wolfSSL/wolfssh)

Patch available: wolfSSL/wolfssh v1.6.0-stable (contains commit 31d13697a608)

https://github.com/wolfSSL/wolfssh/commit/31d13697a608fa1bf9eec11aa6eff1503ade836f
generic

ECDSA host key curve substitution — blob curve not validated against negotiated algorithm (CWE-345) · Issue #1012 · wolfSSL/wolfssh · GitHub

https://github.com/wolfSSL/wolfssh/issues/1012

Vendor Advisories for CVE-2026-16516(1)

These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.

Weakness Classification(1)

MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.

Data Freshness Timeline

(refreshed 11× in last 7d / 11× in last 30d)

Each row is a source pipeline that fetched or updated this CVE on that date, with what changed. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed it from the CNA feed. Most recent first.

  1. 2026-10-07 20:46 UTCGHSA enrichment
  2. 2026-10-07 16:15 UTCGHSA enrichment
  3. 2026-10-07 12:21 UTCEG score recompute
  4. 2026-10-07 12:21 UTCGHSA enrichment
  5. 2026-10-07 11:27 UTCEG score recompute
  6. 2026-10-07 11:27 UTCGHSA enrichment
  7. 2026-10-07 07:44 UTCGHSA enrichment
  8. 2026-10-07 03:31 UTCEG score recompute
  9. 2026-10-07 03:31 UTCGHSA enrichment
  10. 2026-10-07 02:47 UTCEG score recompute
  11. 2026-10-07 02:46 UTCMITRE cvelistV5first tracked

Related CVEs(same CWE)

Frequently asked(4)

What is CVE-2026-16516?
CVE-2026-16516 is a critical vulnerability published on October 7, 2026. 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…
When was CVE-2026-16516 disclosed?
CVE-2026-16516 was first published on October 7, 2026. EchelonGraph re-ingests CVE updates from NVD on a 2-hour cycle, so this page reflects the latest published state.
What is the CVSS score of CVE-2026-16516?
CVE-2026-16516 has a CVSS base score of 9.0 (a secondary CVSS source that NVD displays; NVD's own analysis pending). The EG score is currently aggregating — additional source signals are being incorporated as they become available..
How do I remediate CVE-2026-16516?
A fix for CVE-2026-16516 is available: update to the fixed version the vendor names in its advisory. The vendor advisories EchelonGraph has for CVE-2026-16516 are linked in the Vendor Advisories panel on this page.

Dependency Blast Radius

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