CVE-2026-83742Network attack vectorHinoki check available

Authenticated SFTP crash via path-length underflow

Published Oct 7, 2026 · Updated Oct 7, 2026

Stack buffer overflow in wolfSSL wolfSSH 1.4.11 through 1.5.0 allows remote authenticated users to crash SFTP servers via crafted paths. wolfSSH_RealPath() passes remaining buffer space to wstrncat(), whose unsigned free-space calculation wraps and permits a terminating null byte to land just beyond a stack buffer. The SFTP path requires an authenticated session on a non-Windows build; ordinary copied path data remains in bounds, while callers supplying a smaller output buffer face an unbounded copy.

CVSS severity5.3
Medium
EPSS probability0.39%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

Stack buffer overflow in wolfSSL wolfSSH 1.4.11 through 1.5.0 allows remote authenticated users to crash SFTP servers via crafted paths. wolfSSH_RealPath() passes remaining buffer space to wstrncat(), whose unsigned free-space calculation wraps and permits a terminating null byte to land just beyond a stack buffer. The SFTP path requires an authenticated session on a non-Windows build; ordinary copied path data remains in bounds, while callers supplying a smaller output buffer face an unbounded copy.

The record

CVE
CVE-2026-83742
Published
Oct 7, 2026
Updated
Oct 7, 2026
Vendor
wolfSSL
Product
wolfSSH
Classifications
CWE-193, CWE-191, CWE-121, CAPEC-100, T1499.004
Attack vector
network
Privileges
authenticated

Timeline

How it unfolded

  1. Oct 7, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 7, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=1.4.11 <=1.5.0 changes=[{"at":"1.6.0","status":"unaffected"}]

What conditions does exploitation require?

Attack vectornetwork
Required privilegesauthenticated

What is affected?

wolfSSL · wolfSSHversion=1.4.11 <=1.5.0 changes=[{"at":"1.6.0","status":"unaffected"}]

Published CVSS scores

5.3wolfSSL CNACVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:N/VI:L/VA:L/SC:N/SI:N/SA:N/AU:N

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

Activity data is delayed. The latest report is Sep 28, 2026.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectornetwork
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-193Off-by-one Error
CWE-191Integer Underflow (Wrap or Wraparound)
CWE-121Stack-based Buffer Overflow
CAPEC-100Overflow Buffers
T1499.004Endpoint Denial of Service: Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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