CVE-2026-11826 (GCVE-0-2026-11826)

Vulnerability from cvelistv5 – Published: 2026-07-18 13:35 – Updated: 2026-07-18 13:35
VLAI
Title
OpenPLC_v3 Heap-Based Buffer Overflow in Modbus Master getData()
Summary
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.
Severity
8.7 (High)
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
8.8 (High)
CVSS:3.1/AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
  • CWE-122 - Heap-based Buffer Overflow
Assigner
References
Impacted products
Vendor Product Version
openplcproject OpenPLC_v3 Affected: 0 , ≤ b470206 (git)
Create a notification for this product.
Date Public
2026-07-17 00:00
Credits
Shuhratbek Uraimov Shuhratbek Uraimov
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          "type": "finder",
          "value": "Shuhratbek Uraimov"
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        }
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          "url": "https://github.com/thiagoralves/OpenPLC_v3/commit/b4702061dc14d1024856f71b4543298d77007b88"
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      "source": {
        "discovery": "UNKNOWN"
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    "dateReserved": "2026-06-09T19:53:45.722Z",
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    "state": "PUBLISHED"
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  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

Sightings

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Nomenclature

  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
  • Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
  • Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


Detection rules are retrieved from Rulezet.