CVE-2026-37535
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 · uneditedopenxc/isotp-c thru commit 5a5d19245f65189202719321facd49ce6f5d46ac (2021-08-09) contains an out-of-bounds read in the ISO-TP Single Frame receive handler, where the 4-bit payload length nibble is used directly as the memcpy size without validating it against the actual CAN data length. A malicious CAN frame with an oversized length nibble can cause memory reads beyond the buffer, allowing attackers to cause a denial of service, or gain sensitive information.
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 confidenceThe ISO-TP Single Frame receive handler in openxc/isotp-c uses a 4-bit payload length nibble directly as the memcpy size without validating it against the actual CAN data frame length. An attacker can craft a malicious CAN frame with an oversized length nibble to read beyond buffer boundaries, causing denial of service or leaking sensitive memory contents.
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
- Low
- Integrity
- None
- Availability
- High
CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify if openxc or isotp-c library is in useSearch your codebase, dependencies, or compiled binaries for the openxc or isotp-c library files. Check build files, package manifests, or linker outputs for references to these libraries.Affected if The openxc or isotp-c library is present in your environment
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Determine the installed version of the libraryCheck the version string in the library headers, source files, or library filename. For compiled binaries, use 'strings' or inspect metadata. Compare against any known version releases.Affected if The library version cannot be determined or is an early release prior to any security fixes
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Verify ISO-TP Single Frame reception is enabledInspect your application configuration or code to confirm ISO-TP protocol handling is active. Check for initialization of ISO-TP receive handlers and usage of isotp_recv or similar API functions.Affected if ISO-TP receive functionality is actively used in your application
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Inspect the Single Frame handler for bounds validationIf you have access to source code, locate the Single Frame receive handler function and verify whether length validation occurs before memcpy operations using the payload length nibble. Look for explicit checks comparing extracted length against actual CAN frame data length.Affected if No bounds validation is performed on the 4-bit length nibble before it is used as memcpy size in the Single Frame handler
You are affected if you use the openxc or isotp-c library with ISO-TP receive functionality and the Single Frame handler lacks explicit validation of the payload length nibble against the actual CAN data frame length before memcpy operations.
Generated from the published advisory. Verify against your own configuration.
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 dataImplement bounds validation: verify the extracted length nibble does not exceed the actual CAN data length before using it in memcpy operations. Add explicit length checks in the Single Frame receive handler.
- Consultation3.0 h
- Implementation5.0 h
- Testing5.0 h
- Review / QA2.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $4,176.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-37535 — or any other known-vulnerable package — straight from your lock files. Free and open source; it runs locally and uploads nothing.
References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.
Primary sourcesPractitioner notes
ContributedPeer-ranked notes from engineers who’ve handled CVE-2026-37535 in production — separate from our analysis above.
The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.
- The version that genuinely resolved it — not the one the vendor claimed
- A config change or rule that shut the vector down
- A gotcha in the upgrade path that cost you an afternoon
No notes yet
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- Version or environment caveats, and links to real fixes
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