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CVE-2026-83540

8.8, high

wolfSSL wolfSSH Improper Authentication Vulnerability

NVD (opens in a new tab) CVE.org (opens in a new tab)
CVSS
8.8, high high CVSS v3.1
EPSS, next 30 days
0.4% higher than 28.6% of scored CVEs
Exploitation
No public evidence
Published
7 Oct 202611 days ago

Description

When password or public key authentication is used with the Windows port of wolfSSHd, the Windows logon token acquired for one authenticated connection is not released before a token is acquired for a subsequent connection, resulting in user login poisoning between connections. A less privileged user with a valid account on the server can exploit this to force a login as a more privileged user. The vulnerability was introduced with the initial Windows port of wolfSSHd in wolfSSH version 1.4.15 and affects all versions through 1.5.0. Non-Windows builds of wolfSSHd are not affected.

Details

Vendor
wolfSSL
Product
wolfSSH
Weakness
CWE-287 (opens in a new tab)
Status
Analyzed
Updated
13 Oct 2026
Assigner
facts@wolfssl.com

CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

References 4

Patches and fixes 2

Advisories 1

Other references 1

The kind is read from NVD's tags where present and from the shape of the URL otherwise, so treat it as a hint.

Other wolfSSL CVEs

Every wolfSSL CVE we hold

Same vendor in what we hold, not a known link between the flaws.

  • CVE-2026-89134 A certificate with no dNSName SAN but another SAN type present (e.g EPSS 0.2% 9.1, critical
  • CVE-2026-94418 Under WOLFSSL_SMALL_CERT_VERIFY, ProcessPeerCertParse() runs the certificate signature check separately from the parse to keep peak… EPSS <0.1% 7.5, high
  • CVE-2026-93302 MatchTrustedPeer ignores the public key used, leading to forged CA clones passing verification EPSS 0.2% 8.2, high

Beyond this page

Is CVE-2026-83540 in your network?

This page tells you how dangerous CVE-2026-83540 is out there. Whether it sits on one of your devices, only a scan of your own network can tell. That is what our systems do, every day, for the companies we protect.

  • EXYS7600 OCELOT

    Find it before attackers do

    Ocelot scans your network on a schedule and reports every vulnerability it finds by its CVE identifier, with its CVSS score and how many of your hosts are affected. A finding like CVE-2026-83540 comes with the devices to patch.

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  • EXYS7950 KONDRA

    Detect it if it's exploited

    Until the patch is applied, Kondra monitors your network, events and endpoints in real time. It keeps an inventory of the software installed on every endpoint, and its anomaly detection rules flag what an attacker does once inside.

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Check your exposure

Assembled from the NVD 2.0 API, the CISA Known Exploited Vulnerabilities Catalog and FIRST EPSS. Scores are as of our last collection on 18 Oct 2026, not the live upstream state.