CVE-2025-53888
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 · uneditedRIOT-OS, an operating system that supports Internet of Things devices, has an ineffective size check implemented with `assert()` can lead to buffer overflow in versions up to and including 2025.04. Assertions are usually compiled out in production builds. If assertions are the only defense against untrusted inputs, the software may be exposed to attacks that utilize the lack of proper input checks. In the `l2filter_add()` function shown below, `addr_len` is checked using an assertion and is subsequently used as an argument in a `memcpy()` call. When assertions are disabled, there would be no size check for `addr_len`. As a consequence, if an attacker were to provide an `addr_len` value larger than `CONFIG_L2FILTER_ADDR_MAXLEN`, they can trigger a buffer overflow and write past the `list[i].addr` buffer. If the unchecked input is attacker-controlled, the impact of the buffer overflow can range from a denial of service to arbitrary code execution. Commit f6f7de4ccc107c018630e4c15500825caf02e1c2 contains a patch for the vulnerability.
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 confidenceRIOT-OS contains a buffer overflow vulnerability in the l2filter_add() function where addr_len is validated using assert() before being used in memcpy(). Since assertions are compiled out in production builds, an attacker can provide an addr_len value exceeding CONFIG_L2FILTER_ADDR_MAXLEN to overflow the list[i].addr buffer, potentially causing denial of service or arbitrary code execution.
Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.
Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.
NVD · CPE data<= 2025.04CVSS 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
- Network
- Complexity
- Low
- Privileges
- None
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
CVSS:3.1/AV:N/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 checksWork through these to decide whether this CVE applies to you.
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Identify RIOT-OS version in useCheck the version string of the RIOT-OS codebase or firmware build (e.g., check VERSION file, git tag, or firmware metadata). Compare against <= 2025.04.Affected if The RIOT-OS version is 2025.04 or earlier.
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Verify l2filter module is enabledSearch the build configuration (e.g., .ini, Kconfig, or Makefile.include) for CONFIG_L2FILTER or MODULE_L2FILTER being enabled/compiled in.Affected if The l2filter module (MODULE_L2FILTER) is included in the build.
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Confirm production build configurationCheck if the build is configured as a production release (e.g., -DNDEBUG defined, or CFLAGS lacks -DDEBUG, or Build Type set to Release). Production builds compile out assert() statements.Affected if The firmware is built as a production release with assertions disabled (assert() calls become no-ops).
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Check if l2filter_add() receives external inputReview source code for calls to l2filter_add() function. Determine whether the addr_len parameter can be controlled by external input (e.g., over network, from untrusted sensor data).Affected if l2filter_add() is called with addr_len derived from untrusted external sources.
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Inspect CONFIG_L2FILTER_ADDR_MAXLEN valueCheck the defined value of CONFIG_L2FILTER_ADDR_MAXLEN in the build configuration or header files. Typical value is 8 bytes (64 bits).Affected if CONFIG_L2FILTER_ADDR_MAXLEN is defined, meaning l2filter is present, and an attacker can pass an addr_len larger than this limit.
A user is affected if running RIOT-OS <= 2025.04 with the l2filter module enabled in a production build where l2filter_add() can be called with attacker-controlled addr_len values exceeding CONFIG_L2FILTER_ADDR_MAXLEN.
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.
dbcve · scopedApply the patch from commit f6f7de4ccc107c018630e4c15500825caf02e1c2 which replaces the assert() with proper runtime input validation. Upgrade to the fixed RIOT-OS version once released.
RIOT-OS release version subsequent to 2025.04 (e.g., 2025.05 or later) that includes commit f6f7de4ccc107c018630e4c15500825caf02e1c2
- 1. Identify the current RIOT-OS version in use by checking the version tag or commit hash in the repository.
- 2. Navigate to the RIOT-OS GitHub repository at https://github.com/RIOT-OS/RIOT
- 3. Locate the fix by accessing the patched commit directly: https://github.com/RIOT-OS/RIOT/commit/f6f7de4ccc107c018630e4c15500825caf02e1c2
- 4. Review the changes in the commit to understand the fix (the assertion check is replaced with a proper runtime bounds check for addr_len against CONFIG_L2FILTER_ADDR_MAXLEN before the memcpy call)
- 5. Apply the fix by either: a) cherry-picking commit f6f7de4ccc107c018630e4c15500825caf02e1c2 into your local branch, or b) updating to the RIOT-OS release version that includes this commit
- 6. Rebuild the RIOT-OS image with the patched code
- 7. Redeploy the updated firmware to affected IoT devices
- 8. Verify the fix is correctly applied by reviewing the l2filter_add() function to ensure addr_len is now checked at runtime rather than through assert()
Generated from the published advisory — verify against the referenced sources before acting.
- Consultation4.0 h
- Implementation2.0 h
- Testing4.0 h
- Review / QA2.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2025-53888 — 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-2025-53888 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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