src/internal.c in wolfSSL wolfSSH through 1.5.0 admits the server-to-client Diffie-Hellman group exchange messages SSH_MSG_KEX_DH_GEX_GROUP (31) and SSH_MSG_KEX_DH_GEX_REPLY (33) when a server receives them from an unauthenticated client. IsMessageAllowedServer() applies no direction check to the key exchange message range: when the peer is keying and no particular message is expected, which is the state a server is in for the whole window after it processes the client's KEXINIT because nothing sets handshake->expectMsgId there, the function falls out of its expectation branch without a verdict and reaches a numeric bound that admits every message id from 30 through 34. A client that negotiates diffie-hellman-group-exchange-sha256 and then sends message 31 makes the server run the client-side handler DoKexDhGexGroup(), which validates the attacker-supplied group with two 8-round Miller-Rabin primality tests, one on p and one on (p-1)/2, on a value of up to 8192 bits. The handler then returns success: the server stores the attacker's prime and generator, generates a Diffie-Hellman key pair in the attacker's group, and sends the client-role message SSH_MSG_KEX_DH_GEX_INIT (32) back to the attacker. Published RFC 3526 safe primes are the worst-case input and cost the attacker nothing to obtain. The primality validation was added in 1.5.0; versions from 1.2.0 through 1.4.22 admit the same message and enter the same client-role path without the primality cost. Message 33 is admitted as well, but on a server it is rejected before any cryptography because no public key check callback is registered, so it carries no comparable cost. Builds that define WOLFSSH_NO_DH_GEX_SHA256, which is implied by WOLFSSH_NO_DH or NO_SHA256, are unaffected.
CVE-2026-84897
“—” beside the score: it is equal to NVD's CVSS score.
Score 5.3 from GitHub Security Advisory published 2026-10-07. NVD baseline CVSS 5.3; sources differ by 0.0.
Also known asEUVD-2026-94165 (ENISA EUVD) · GHSA-39q2-5h5r-39p7 (GitHub Security Advisories)Source: ENISA EUVD
- Lower severity and no public exploit yet
A fix is available — apply it.
- CVSS v3
- 5.3
- EG Score
- 5.3MEDIUMhigh confidence
- EG Risk
- 39EG Risk 39/100
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)Severity53% × 45%Impact severity (EG Severity): CVSS 5.3 of 10. Never the KEV-floored or EPSS-lifted EG Score.Exploitation0.5% × 40%FIRST EPSS: the 30-day exploitation probability when EchelonGraph scored this CVE.Automatability100% × 15%CISA's SSVC Automatable value: yes (Vulnrichment).SSVC (CISA's decision table, applied by EchelonGraph): Track at low or medium mission impact; Attend at high (mission-essential systems).Exploitation none (CISA Vulnrichment) · Automatable yes (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 at low or medium mission impact and sooner than that at high. - EPSS PROB
- 0.5%
- EPSS %ILE
- 41st
- 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 (5.3): severity, escalated by confirmed exploitation. This CVE's 5.3 is its impact severity (EG Severity), not escalated.
- EG Severity
- 5.3 MEDIUMCVSS-B, impact only: no KEV listing, EPSS or EG-KEV tier raises it.GitHub Security Advisory CVSS
- EG Likelihood
- 0.5% within 30 daysSource: FIRST EPSS (model v2026.06.15, score date 2026-10-29). 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 low or medium mission impact; Attend at high (mission-essential systems).CISA BOD 26-04: 14 days if the affected system is publicly exposed; 60 days 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 low or medium mission impact; Attend at high (mission-essential systems).
A fix is available. Apply it within your standard update timelines at low or medium mission impact and sooner than that at high.
Exploitation none (CISA Vulnrichment) · Automatable yes (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)14 days if the affected system is publicly exposed; 60 days if it is not.
The score's inputs: In CISA KEV no (CISA's KEV catalog) · Automatable yes (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 (4)
Auto-updated Oct 7, 2026commit a472f1ee2b65 (wolfSSL/wolfssh)
Patch available: wolfSSL/wolfssh v1.6.0-stable (contains commit a472f1ee2b65)
https://github.com/wolfSSL/wolfssh/commit/a472f1ee2b653f623d85ef2297321733f1dbfd22Reject the KEX replies a server never receives
Patch available: wolfSSL/wolfssh v1.6.0-stable (PR #1221 merged 2026-09-02)
https://github.com/wolfSSL/wolfssh/pull/1221Vendor Advisories for CVE-2026-84897(1)
These vendors published their own advisory mentioning this CVE — often with vendor-specific remediation steps + affected product lists not in NVD.
Weakness Classification(3)
MITRE Common Weakness Enumeration — the root-cause categories this CVE belongs to.
Data Freshness Timeline
(refreshed 9× in last 7d / 55× 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 it from the CNA feed. 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). Most recent first.
- 2026-11-01 16:35 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-31 16:33 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-30 16:35 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-29 17:06 UTCEG score recompute
- 2026-10-29 17:06 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7 · GitHub CVSS 5.3
- 2026-10-29 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-28 16:33 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-27 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-26 16:32 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-25 16:34 UTCEPSS rescoreEPSS 0.5% · 41st percentile
- 2026-10-25 13:56 UTCEG score recompute
- 2026-10-24 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-23 16:32 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-22 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-22 12:56 UTCEG score recompute
- 2026-10-22 12:56 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7 · GitHub CVSS 5.3
- 2026-10-21 16:34 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-20 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-19 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-18 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-18 03:06 UTCEG score recompute
- 2026-10-17 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-16 16:44 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-15 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-14 16:33 UTCEPSS rescoreEPSS 0.3% · 21st percentile
Show 30 moreShow fewer
- 2026-10-13 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-13 14:47 UTCEG score recompute▼ 1.60
- 2026-10-13 14:46 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-13 14:44 UTCNVD updateCVSS v3 → 5.3
- 2026-10-12 16:35 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-12 14:53 UTCEG score recompute
- 2026-10-11 19:18 UTCEG score recompute
- 2026-10-11 16:34 UTCEG score recompute
- 2026-10-11 13:52 UTCEG score recompute
- 2026-10-11 13:49 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-11 12:35 UTCEG score recompute
- 2026-10-11 12:34 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-10 20:00 UTCEPSS rescoreEPSS 0.3% · 21st percentile
- 2026-10-10 14:20 UTCEG score recompute
- 2026-10-10 14:20 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-09 20:07 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-09 16:06 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-08 17:51 UTCEG score recompute
- 2026-10-08 17:51 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-08 17:13 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-07 23:48 UTCEPSS rescoreEPSS 0.3% · 20th percentile
- 2026-10-07 19:21 UTCEG score recompute
- 2026-10-07 19:21 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-07 18:47 UTCEG score recompute
- 2026-10-07 18:47 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-07 16:15 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-07 03:31 UTCEG score recompute
- 2026-10-07 03:31 UTCGHSA enrichmentGHSA-39q2-5h5r-39p7
- 2026-10-07 03:02 UTCEG score recomputeFirst assessed: 6.9 MEDIUM
- 2026-10-07 03:01 UTCMITRE cvelistV5first tracked
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Frequently asked(5)
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Dependency Blast Radius
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