---
title: "CVE-2026-83742: wolfSSL wolfSSH - Integer Overflow"
description: "wolfSSL wolfSSH v1.4.11 through v1.5.0 on non-Windows platforms contains an unsigned integer underflow in wstrncat() in src/port.c, letting authenticated remote attackers write one out-of-bounds null byte past a stack buffer by sending crafted SFTP paths, exploit requires authentication."
url: https://panop.io/threat-heartbeat/CVE-2026-83742/
---

# CVE-2026-83742 wolfSSL wolfSSH - Integer Overflow

wolfSSL wolfSSH v1.4.11 through v1.5.0 on non-Windows platforms contains an unsigned integer underflow in wstrncat() in src/port.c, letting authenticated remote attackers write one out-of-bounds null byte past a stack buffer by sending crafted SFTP paths, exploit requires authentication.

CVSS base score 8.8 /10

High

CISA KEV

Not listed

Public exploit

None known

Authentication

Required

EPSS

0.39% chance of exploitation in 30 days

[View the NVD record ↗](https://nvd.nist.gov/vuln/detail/CVE-2026-83742)

## Details

Type

Integer Overflow

Impact

Denial Of Service

CVSS vector

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

Published

7 October 2026

Updated

15 October 2026

Weakness

[CWE-121](https://cwe.mitre.org/data/definitions/121.html)

## Vendor fix

Update to a version later than v1.5.0 or the latest available version.

Patching closes this CVE. It does not tell you which of your systems run the affected version, or what else is exposed alongside them.

## References

- [https://nvd.nist.gov/vuln/detail/CVE-2026-83742](https://nvd.nist.gov/vuln/detail/CVE-2026-83742)
- [https://github.com/wolfSSL/wolfssh/commit/822e4464560b467580ea37a2fc03b0988d88b71f](https://github.com/wolfSSL/wolfssh/commit/822e4464560b467580ea37a2fc03b0988d88b71f)
- [https://github.com/wolfSSL/wolfssh/commit/fbc7cd88a23b59a45a584020a4c7242d9bd70f35](https://github.com/wolfSSL/wolfssh/commit/fbc7cd88a23b59a45a584020a4c7242d9bd70f35)
- [https://github.com/wolfSSL/wolfssh/pull/1084](https://github.com/wolfSSL/wolfssh/pull/1084)
- [https://github.com/wolfSSL/wolfssh/commit/513e52b18927a4e3f7cf17ecaf107958e56139de](https://github.com/wolfSSL/wolfssh/commit/513e52b18927a4e3f7cf17ecaf107958e56139de)

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## What this record can't tell you

- Whether you run the affected software, and where
- Whether an attacker can actually reach and exploit it
- The misconfigurations that never get a CVE number
- What it would cost the business, ranked into what to fix first

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