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CVE-2026-83742

8.8, high

wolfSSL Inc. wolfSSH Stack-based Buffer Overflow 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 31.7% of scored CVEs
Exploitation
No public evidence
Published
7 Oct 202610 days ago

Description

Unsigned integer underflow in wstrncat() in src/port.c in wolfSSL wolfSSH from v1.4.11 through v1.5.0 on non-Windows platforms allows an authenticated remote attacker to write one out-of-bounds null byte past the end of a stack buffer by sending a crafted SFTP path. wolfSSH_RealPath() in src/ssh.c appends each path component with a remaining-size bound (outSz - curSz) rather than the full destination size, so once the accumulated path reaches half the output buffer the size_t computation n - strlen(s1) - 1 wraps to near SIZE_MAX. The strncat() call is then effectively unbounded and copies the whole component; when that component exactly fills the remainder of the buffer, its terminating null is written one byte past the end. The caller's own length check keeps the copied data inside the buffer, so the overflow is limited to that single null byte, which may corrupt an adjacent stack value and crash the process. Applications that call the public wolfSSH_RealPath() with an output buffer smaller than the input path are additionally exposed to an unbounded copy, because the word32 expression outSz - segSz in that length check also wraps.

Details

Vendor
wolfSSL Inc.
Product
wolfSSH
Weakness
CWE-121 (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 4

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 Inc. CVEs

Every wolfSSL Inc. CVE we hold

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

  • CVE-2026-81535 wolfSSL Inc. wolfSSH Missing Authorization Vulnerability EPSS 0.3% 9.1, critical
  • CVE-2026-16516 wolfSSH does not validate that the ECDSA curve identifier in a KEXDH_REPLY host key blob matches the algorithm negotiated during key… EPSS 0.1% 7.4, high

Beyond this page

Is CVE-2026-83742 in your network?

This page tells you how dangerous CVE-2026-83742 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-2026-83742 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 17 Oct 2026, not the live upstream state.