High · CVSS 7.7CVE-2026-83540

wolfSSHd on Windows race condition leading to logon token reused across connectionsCVE-2026-83540

Answer in brief

CVE-2026-83540 records a High severity (CVSS 7.7) vulnerability in wolfSSHd on Windows race condition leading to logon token reused across connections. The current sources do not mark it as known exploited. The current feed maps wolfSSL/wolfSSH (generic). Check affected ranges and fixed versions before updating.

Analysis pending evidence review

HOL Guard separates source facts from reviewed analysis. See the methodology.

Published Oct 7, 2026Updated Oct 7, 2026Source checked Oct 7, 2026First seen by HOL Oct 7, 2026Material review Oct 7, 2026

Upstream Advisory

Key facts

Risk: High · CVSS 7.7
Exploitation: Not marked as known exploited
Affected software: 1 mapped package or product
Fix availability: Not reported

Why this deserves its current priority

CVSS is 7.7. The current sources do not mark it as known exploited. Treat this as a source-backed prioritization signal, not a statement about your environment.

Analysis status

Analysis pending evidence review

Factual feed record only; HOL analysis is not approved for indexing. Read the methodology.

Affected scope and exposure questions

The current feed maps wolfSSL/wolfSSH (generic). Check affected ranges and fixed versions before updating.

Mapped affected packages and fixed versions
Package	Affected range	Fixed version
wolfSSL/wolfSSHgeneric	>=1.4.15 <=1.5.0	Not reported

Recommended response

Check inventory. Check lockfiles and deployed manifests for wolfSSL/wolfSSH.
Review the reported fix. Source-reported workaround: Restrict which accounts may connect to the affected wolfSSHd instance on Windows hosts until the server is upgraded. Disabling public key authentication alone does not help, because password authentication is affected as well.

Evidence timeline and material changes

Published upstream
Oct 7, 2026
Evidence: source:cvelist:source_dates:source-dates:record
Source modified
Oct 7, 2026
Evidence: source:cvelist:source_dates:source-dates:record
First seen by HOL
Oct 7, 2026

Sources and claim methodology

Upstream source 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.

Quoted source text, attributed separately from HOL analysis.