CVE-2026-11826

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Source

https://cve.org/CVERecord?id=CVE-2026-11826

Import Source

https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11826.json

JSON Data

https://api.osv.dev/v1/vulns/CVE-2026-11826

Published

2026-07-18T13:35:35Z

Modified

2026-10-21T09:41:59Z

Severity

8.7 (High) CVSS_V4 - CVSS:4.0/AV:N/AC:L/AT:N/PR:L/UI:N/VC:H/VI:H/VA:H/SC:N/SI:N/SA:N CVSS Calculator

Summary

OpenPLC_v3 Heap-Based Buffer Overflow in Modbus Master getData()

Details

OpenPLC_v3 contains a heap-based buffer overflow in the getData() function in webserver/core/modbus_master.cpp. getData() reads characters between two delimiters into a caller-supplied buffer with no size parameter and no bounds check. In parseConfig() the function is invoked with the 100-byte heap-allocated MB_device.dev_name field. An authenticated attacker with access to the OpenPLC web interface can send a crafted HTTP POST to the /modbus endpoint with an oversized device_name value; the value is persisted to mbconfig.cfg and parsed on load, overflowing dev_name and overwriting adjacent struct fields (protocol at offset 108, dev_address at offset 109, ip_port at offset 210). A 200-byte payload writes 100 bytes past the allocation. The result is heap corruption leading to runtime crash and denial of service of the PLC process control loop, with attacker-controlled overwrite of adjacent configuration fields. The upstream repository was archived on 2026-04-04 and no fix is expected; the vendor has confirmed the issue does not affect OpenPLC Runtime v4.

Database specific

{
    "cna_assigner":  "VulnCheck",
    "cwe_ids":  [
        "CWE-122"
    ],
    "osv_generated_from":  "https://github.com/CVEProject/cvelistV5/tree/main/cves/2026/11xxx/CVE-2026-11826.json"
}

References

Affected packages

Git / github.com/thiagoralves/openplc_v3

Affected ranges

Type

GIT

Repo

https://github.com/thiagoralves/openplc_v3

Events

Introduced

Fixed

b4702061dc14d1024856f71b4543298d77007b88

Database specific

Show details

{
    "extracted_events":  [
        {
            "range":  [
                {
                    "introduced":  "0"
                },
                {
                    "last_affected":  "b470206"
                }
            ],
            "source":  "AFFECTED_FIELD",
            "strategy":  "StandardRange"
        },
        {
            "range":  [
                {
                    "fixed":  "b4702061dc14d1024856f71b4543298d77007b88"
                }
            ],
            "source":  "REFERENCES_COMMIT"
        }
    ]
}

Database specific

source

"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2026-11826.json"

vanir_signatures

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    {
        "deprecated":  false,
        "digest":  {
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            "threshold":  0.9
        },
        "id":  "CVE-2026-11826-eecd8351",
        "signature_type":  "Line",
        "signature_version":  "v1",
        "source":  "https://github.com/thiagoralves/openplc_v3/commit/b4702061dc14d1024856f71b4543298d77007b88",
        "target":  {
            "file":  "webserver/core/lib/iec_std_functions.h"
        }
    }
]

vanir_signatures_modified

"2026-10-21T09:41:59Z"