CVE-2026-16516

HIGHNVD 7.47.4
EchelonGraph scoreMEDIUM confidence

“—” beside the score: it is equal to NVD's CVSS score.

Score 7.4 from GitHub Security Advisory (severity: CRITICAL) published 2026-10-07. NVD baseline CVSS 7.4; sources differ by 0.0.

Triggered by: GitHub Security Advisory CVSS
Sources: EPSS, GitHub Security Advisory, NVD CVSS v3

Also known asEUVD-2026-94161 (ENISA EUVD) · GHSA-c487-h25j-24jq (GitHub Security Advisories)Source: ENISA EUVD

7.4EG
EchelonGraph verdictPlan a fixRemediate within your standard update timelines (the SSVC decision on this page).
  • High severity, but no confirmed exploitation yet
CISA-KEV: Not listedEPSS PROB: 0.2%CVSS: 7.4Exploit: 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
7.4
EG Score
7.4HIGHmedium confidence
EG Risk
33
EG Risk 33/100

EG Risk is EchelonGraph's 0–100 priority score. It fuses impact severity (EG Severity, the CVSS base score, never the KEV-floored or EPSS-lifted EG Score) with real-world exploitation and automatability, under weights EchelonGraph set by hand, so you can rank equal-severity CVEs and fix the most dangerous first. Higher = act sooner.

How it’s computed (value × EchelonGraph’s weight)
Severity74% × 45%
Impact severity (EG Severity): CVSS 7.4 of 10. Never the KEV-floored or EPSS-lifted EG Score.
Exploitation0.2% × 40%
FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.
Automatability0% × 15%
CISA's SSVC Automatable value: no (Vulnrichment).
SSVC (CISA's decision table, applied by EchelonGraph): Track at every mission impact level.
Exploitation none (CISA Vulnrichment) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE.
Action: A fix is available. Apply it within your standard update timelines.
EPSS PROB
0.2%
EPSS %ILE
8th
KEV
Not listed

What the EG score is made of (scorer v4.0: the three questions the 0–10 score mixes, published apart · methodology)

The EG score (7.4): severity, escalated by confirmed exploitation. This CVE's 7.4 is its impact severity (EG Severity), not escalated.

EG Severity
7.4 HIGHCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
EG Likelihood
0.2% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-11-10). FIRST's exploitation probability, not an EchelonGraph model.
Confirmed exploitation
None on record (CISA KEV, EG-KEV Tier 1)Reported apart from the likelihood: an observed fact, not a probability.
EG Priority
SSVC Track at medium mission impactTrack at every mission impact level.CISA BOD 26-04: 60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.Each input and its source, and whom BOD 26-04 binds: the SSVC and BOD 26-04 blocks below.

SSVC (CISA's decision table, applied by EchelonGraph)Track 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). All three are CISA's SSVC values (Vulnrichment). EchelonGraph applied CISA's decision table to them; CISA publishes SSVC inputs and the table, not a decision for each CVE. Mission impact is CISA's Mission & Well-being decision point, and only you can judge it. CISA's table makes it high when Mission Prevalence is Essential — the vulnerable component "directly provides capabilities that constitute at least one MEF for at least one entity" (MEF: mission essential function) — or when Public Well-Being Impact is Irreversible: "multiple fatalities are likely", the cyber-physical system "is likely lost or destroyed", "extreme or serious externalities" are imposed on other parties, or social systems such as elections or the financial grid "are destabilized and potentially collapse". CISA's decision table

BOD 26-04 (CISA's remediation timeline, Table 1)60 days if the affected system is publicly exposed; Fix on system upgrade if it is not.

The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable no (CISA Vulnrichment) · Technical impact partial (CISA Vulnrichment). Whether your system is publicly exposed is yours to answer. BOD 26-04 binds US Federal Civilian Executive Branch agencies; for anyone else it is CISA's published timeline, a reference rather than an obligation. The directive · how EchelonGraph applies it

Published

October 7, 2026

Last Modified

October 13, 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
Web page

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.

Affected Packages

(1 across 1 ecosystem)
Alpine:v3.24(1)
PackageVulnerable rangeFix by version rangeDependents
wolfssh—
  • every version up to 1.6.0-r0: fixed in 1.6.0-r0
—

Weakness Classification(1)

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

Data Freshness Timeline

(refreshed 8× in last 7d / 33× in last 30d)

Each row is a time one of our pipelines fetched, updated or re-scored this CVE. For example, "NVD update" means NVD published or revised its analysis for this CVE; "MITRE cvelistV5" means we ingested or refreshed its CVE.org record (CNA or CISA ADP). An arrow marks a change the record states ("CVSS v3 → 9.1"); EPSS and GHSA rows show the values recorded at that time, not what changed (EPSS values are rounded; hover one for the exact figures). "EchelonGraph re-scored" is our own recompute of this CVE's score, not an update from a source, and is not counted in the refreshes above. Most recent first.

  1. 2026-11-12 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  2. 2026-11-11 16:38 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  3. 2026-11-11 03:52 UTCEchelonGraph re-scored
  4. 2026-11-11 03:52 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL · GitHub CVSS 7.4
  5. 2026-11-10 16:42 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  6. 2026-11-09 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  7. 2026-11-08 16:38 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  8. 2026-11-07 16:38 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  9. 2026-11-06 16:36 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  10. 2026-11-06 03:32 UTCEchelonGraph re-scored
  11. 2026-11-06 03:32 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL · GitHub CVSS 7.4
  12. 2026-11-05 16:36 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  13. 2026-11-04 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  14. 2026-11-03 20:15 UTCEchelonGraph re-scored
  15. 2026-11-03 20:15 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL · GitHub CVSS 7.4
  16. 2026-11-03 16:47 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  17. 2026-11-02 16:44 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  18. 2026-11-01 16:34 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  19. 2026-10-31 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  20. 2026-10-30 16:33 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  21. 2026-10-29 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  22. 2026-10-28 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  23. 2026-10-27 20:53 UTCEchelonGraph re-scored
  24. 2026-10-27 20:53 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL · GitHub CVSS 7.4
  25. 2026-10-27 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
Show 70 more
  1. 2026-10-26 16:31 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  2. 2026-10-25 16:32 UTCEPSS rescoreEPSS 0.2% · 8th percentile
  3. 2026-10-25 14:46 UTCEchelonGraph re-scored
  4. 2026-10-24 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  5. 2026-10-23 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  6. 2026-10-22 16:34 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  7. 2026-10-21 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  8. 2026-10-20 19:07 UTCEchelonGraph re-scored
  9. 2026-10-20 19:07 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL · GitHub CVSS 7.4
  10. 2026-10-20 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  11. 2026-10-18 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  12. 2026-10-18 04:00 UTCEchelonGraph re-scored
  13. 2026-10-16 16:40 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  14. 2026-10-15 16:31 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  15. 2026-10-14 16:32 UTCEPSS rescoreEPSS 0.1% · 1st percentile
  16. 2026-10-13 17:46 UTCEchelonGraph re-scored▼ 1.60
  17. 2026-10-13 17:45 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  18. 2026-10-13 17:44 UTCNVD updateCVSS v3 → 7.4 · severity → HIGH
  19. 2026-10-13 16:33 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  20. 2026-10-12 22:55 UTCEchelonGraph re-scored
  21. 2026-10-12 22:55 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  22. 2026-10-12 16:33 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  23. 2026-10-12 16:30 UTCEchelonGraph re-scored
  24. 2026-10-12 03:52 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  25. 2026-10-11 23:38 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  26. 2026-10-11 19:23 UTCEchelonGraph re-scored
  27. 2026-10-11 19:23 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  28. 2026-10-11 17:21 UTCEchelonGraph re-scored
  29. 2026-10-11 15:10 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  30. 2026-10-11 14:54 UTCEchelonGraph re-scored
  31. 2026-10-11 13:48 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  32. 2026-10-11 10:55 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  33. 2026-10-11 06:40 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  34. 2026-10-11 02:27 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  35. 2026-10-10 22:13 UTCEchelonGraph re-scored
  36. 2026-10-10 22:12 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  37. 2026-10-10 19:59 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  38. 2026-10-10 17:54 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  39. 2026-10-10 13:42 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  40. 2026-10-10 09:30 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  41. 2026-10-10 05:18 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  42. 2026-10-10 01:06 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  43. 2026-10-09 20:53 UTCEchelonGraph re-scored
  44. 2026-10-09 20:53 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  45. 2026-10-09 20:06 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  46. 2026-10-09 16:40 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  47. 2026-10-09 12:26 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  48. 2026-10-09 08:13 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  49. 2026-10-09 04:01 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  50. 2026-10-08 23:48 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  51. 2026-10-08 19:36 UTCEchelonGraph re-scored
  52. 2026-10-08 19:36 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  53. 2026-10-08 17:11 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  54. 2026-10-08 15:13 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  55. 2026-10-08 09:24 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  56. 2026-10-08 05:11 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  57. 2026-10-08 00:59 UTCEchelonGraph re-scored
  58. 2026-10-08 00:59 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  59. 2026-10-07 23:47 UTCEPSS rescoreEPSS 0.1% · 3rd percentile
  60. 2026-10-07 20:46 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  61. 2026-10-07 16:15 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  62. 2026-10-07 12:21 UTCEchelonGraph re-scored
  63. 2026-10-07 12:21 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  64. 2026-10-07 11:27 UTCEchelonGraph re-scored
  65. 2026-10-07 11:27 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  66. 2026-10-07 07:44 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  67. 2026-10-07 03:31 UTCEchelonGraph re-scored
  68. 2026-10-07 03:31 UTCGHSA enrichmentGHSA-c487-h25j-24jq · GitHub severity CRITICAL
  69. 2026-10-07 02:47 UTCEchelonGraph re-scoredFirst assessed: 9.0 CRITICAL
  70. 2026-10-07 02:46 UTCMITRE cvelistV5first tracked

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Frequently asked(5)

What is CVE-2026-16516?
CVE-2026-16516 is a high-severity vulnerability; its CVE record was 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 the CVE record for CVE-2026-16516 published?
The CVE record for CVE-2026-16516 was published on October 7, 2026. That is the record's publication date; the vulnerability itself may have been made public earlier. EchelonGraph's copy of the record carries a last-modified date of October 13, 2026; the record at its source may have been updated since.
Is CVE-2026-16516 actively exploited?
CVE-2026-16516 is not currently on CISA's Known Exploited Vulnerabilities catalog. FIRST EPSS estimates a 0.2% probability of exploitation in the next 30 days (8th percentile of EPSS-scored CVEs).
What is the CVSS score of CVE-2026-16516?
CVE-2026-16516 has a CVSS v3 base score of 7.4 (NVD).
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.

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