CVE-2026-83742

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Source

https://cve.org/CVERecord?id=CVE-2026-83742

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-83742.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-83742

Published

2026-10-07T02:41:48Z

Modified

2026-10-09T07:06:13Z

Severity

5.3 (Medium) CVSS_V4 - CVSS: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 Calculator

Summary

wstrncat() unsigned integer underflow leads to an off-by-one null write in wolfSSH on non-Windows platforms

Details

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.

Database specific

{
    "cna_assigner": "wolfSSL",
    "cwe_ids": [
        "CWE-121",
        "CWE-191",
        "CWE-193"
    ],
    "osv_generated_from": "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/83xxx/CVE-2026-83742.json",
    "unresolved_ranges": [
        {
            "extracted_events": [
                {
                    "introduced": "1.4.11"
                },
                {
                    "fixed": "1.6.0"
                }
            ],
            "source": "AFFECTED_FIELD"
        }
    ]
}

References

Affected packages

Git / github.com/wolfssl/wolfssh

Affected ranges

Type

GIT

Repo

https://github.com/wolfssl/wolfssh

Events

Introduced

d42230d629808cfc32762c66ab9f28f9148987ae

Fixed

8643d7be841184f766374e3b0ed68ced6391543c

Fixed

513e52b18927a4e3f7cf17ecaf107958e56139de

Fixed

822e4464560b467580ea37a2fc03b0988d88b71f

Fixed

fbc7cd88a23b59a45a584020a4c7242d9bd70f35

Database specific

Show details

{
    "extracted_events": [
        {
            "introduced": "v1.4.11"
        },
        {
            "fixed": "v1.5.0"
        }
    ],
    "source": [
        "DESCRIPTION",
        "REFERENCES"
    ]
}

Affected versions

v1.*

v1.4.11-stable

v1.4.12-stable

v1.4.13-stable

v1.4.14-stable

v1.4.15-stable

v1.4.16

v1.4.17-stable

v1.4.18-stable

v1.4.19-stable

v1.4.20-stable

v1.4.21-stable

v1.4.22-stable

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-83742.json"

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vanir_signatures_modified

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