CVE-2026-56786
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 · uneditedRTKLIB through 2.4.3 contains an out-of-bounds write vulnerability in decode_type1033 function that fails to clamp length counters to destination buffer size, allowing up to 191-byte overflow into fixed 64-byte descriptor fields. An attacker controlling an NTRIP or serial RTCM3 correction stream can craft a valid CRC-bearing type-1033 message to corrupt adjacent rtcm_t object members, potentially achieving arbitrary code execution or denial of service.
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 confidenceRTKLIB through 2.4.3 has an out-of-bounds write in decode_type1033 where length counters are not clamped to the destination buffer size, allowing up to 191 bytes to overflow into adjacent 64-byte descriptor fields. Attackers can exploit this via crafted NTRIP or serial RTCM3 type-1033 messages with valid CRC to corrupt rtcm_t object members and potentially achieve 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<= 2.4.3CVSS 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 RTKLIB versionCheck the version of the installed RTKLIB library or application (commonly found via 'rtklib_version' symbol, or check application About dialog, or examine the shared library/binary file for version strings)Affected if The installed version is RTKLIB 2.4.3 or any earlier version (versions through 2.4.3 are affected)
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Confirm RTCM3 input is enabledInspect the RTKLIB configuration or stream settings to determine if RTCM3 message input is enabled (this is typically configured in the input stream settings for NTRIP, serial, or file input)Affected if RTCM3 input streams are enabled and receiving data from untrusted sources (NTRIP caster, serial port, or network)
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Verify type-1033 message processingExamine runtime logs or debug output to confirm that RTCM3 type-1033 messages are being received and decoded by the rtcm_t decoderAffected if The system processes RTCM3 type-1033 messages from any input source without filtering them out
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Check input source trust levelReview the configuration for RTCM3 input sources (NTRIP connections, serial ports, TCP/UDP streams) and determine whether they accept connections from untrusted or external sourcesAffected if RTCM3 input is accepted from untrusted or non-local sources without additional validation
You are affected if RTKLIB version 2.4.3 or earlier is in use AND RTCM3 type-1033 messages from any input source are being processed by the decode_type1033 function.
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 dataUpgrade to RTKLIB version 2.4.4 or later which implements proper bounds checking; alternatively, validate and filter incoming RTCM3 streams at network boundary ingress points before reaching the RTKLIB parser.
- Consultation4.0 h
- Implementation8.0 h
- Testing8.0 h
- Review / QA4.0 h
An estimate, not a bill — we confirm scope with you before any work starts. Need it this week? Rush from $6,656.
Scan for this in your stack
Free · runs locallyCheck whether your project pulls in CVE-2026-56786 — 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-2026-56786 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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- Verified mitigations, workarounds, and config changes
- Version or environment caveats, and links to real fixes
- No weaponised exploit code, or anything meant to cause harm
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