Stack-based Buffer OverflowWeakness · CWE-121

CVE-2026-37536

HIGH · 8.8 CVSS v3.1 Published 2026-05-01
Mitigation only
No fix yet — a mitigation exists. There is no fixed release. A documented workaround reduces exposure in the meantime.
See remediation →
93/100
Remediation priority · Urgent
No privileges Zero-click

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
miaofng/uds-c commit e506334e270d77b20c0bc259ac6c7d8c9b702b7a (2016-10-05) contains a stack buffer overflow in send_diagnostic_request. A 6-byte stack buffer (MAX_DIAGNOSTIC_PAYLOAD_SIZE=6) receives memcpy at offset 1+pid_length with payload_length bytes. MAX_UDS_REQUEST_PAYLOAD_LENGTH=7, so 1+2+7=10 exceeds buffer by 4 bytes. No bounds check on payload_length before memcpy.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

Stack buffer overflow in send_diagnostic_request where a 6-byte stack buffer (MAX_DIAGNOSTIC_PAYLOAD_SIZE=6) receives memcpy with payload_length bytes at offset 1+pid_length. With MAX_UDS_REQUEST_PAYLOAD_LENGTH=7, the copy attempts to write 10 bytes (1+2+7) into a 6-byte buffer, overflowing by 4 bytes. No bounds check validates payload_length before the memcpy operation.

MitigationAdd bounds checking to ensure payload_length + 1 + pid_length does not exceed MAX_DIAGNOSTIC_PAYLOAD_SIZE before memcpy, or increase buffer size to accommodate maximum possible payload.

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Adjacent
Complexity
Low
Privileges
None
User interaction
None
Scope
Unchanged
Confidentiality
High
Integrity
High
Availability
High

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

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Locate the send_diagnostic_request function source code
    Search the codebase for the function 'send_diagnostic_request' and review its implementation to identify the memcpy operation
    Affected if The function exists and performs a memcpy into a fixed-size buffer without bounds checking on payload_length
  2. Verify MAX_DIAGNOSTIC_PAYLOAD_SIZE buffer size
    Find the definition of MAX_DIAGNOSTIC_PAYLOAD_SIZE in the codebase - it should be defined as 6 bytes
    Affected if MAX_DIAGNOSTIC_PAYLOAD_SIZE is defined as 6 and is used as the destination buffer size for the memcpy
  3. Confirm MAX_UDS_REQUEST_PAYLOAD_LENGTH value
    Find the definition of MAX_UDS_REQUEST_PAYLOAD_LENGTH - it should be 7 bytes
    Affected if MAX_UDS_REQUEST_PAYLOAD_LENGTH is 7, allowing payload_length up to 7 bytes which exceeds the 6-byte buffer when combined with offset bytes
  4. Inspect the memcpy call for missing bounds check
    Review the memcpy call in send_diagnostic_request: it copies payload_length bytes at offset (1+pid_length) into the buffer; verify there is no validation that payload_length + 1 + pid_length <= buffer size before the copy
    Affected if The memcpy operates without validating that the total bytes to write (1 + pid_length + payload_length) does not exceed the buffer size (6 bytes)
  5. Calculate overflow condition
    When pid_length is 2 and payload_length is at maximum (7), the copy attempts to write 1+2+7=10 bytes into a 6-byte buffer, overflowing by 4 bytes
    Affected if The code allows payload_length up to 7 with pid_length of 2, resulting in a 4-byte overflow

The environment is affected if it contains the send_diagnostic_request function with a 6-byte MAX_DIAGNOSTIC_PAYLOAD_SIZE buffer and a memcpy that lacks bounds validation, allowing payload_length + 1 + pid_length to exceed 6 bytes.

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

From vendor data
Mitigation available No clean upgrade yet — mitigate in the meantime
Mitigation

Add bounds checking to ensure payload_length + 1 + pid_length does not exceed MAX_DIAGNOSTIC_PAYLOAD_SIZE before memcpy, or increase buffer size to accommodate maximum possible payload.

Have this fixed Scoped from the published advisory
  • Consultation2.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
6.0 hours of engineering $1,060
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-37536 in production — separate from our analysis above.

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