CVE-2026-8479
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 · uneditedIEC 60870-5-104 used in bidirectional mode in RTU500 is vulnerable for a NULL pointer dereferencing, if a specially crafted sequence of messages is sent for a certain time, causing Denial of Service impact. Product is only affected if IEC 60870-5-104 functionality in bidirectional mode (BCI) is configured.
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 · moderate confidenceA NULL pointer dereference vulnerability exists in the IEC 60870-5-104 protocol implementation in RTU500 products when configured in bidirectional mode (BCI). An attacker can send a specially crafted sequence of messages over time to trigger the NULL pointer dereference, causing a denial of service condition.
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
- Low
- Authentication
- X
- User interaction
- None
- Scope
- X
CVSS:4.0/AV:A/AC:L/AT:N/PR:L/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X
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 the RTU500 product installationLocate the RTU500 device or software on your network and confirm it is from the vendor providing IEC 60870-5-104 protocol support. Check system inventory or network documentation for RTU500 references.Affected if The system is not an RTU500 product - this CVE does not apply.
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Determine the installed RTU500 versionAccess the RTU500 management interface, CLI, or system information file and retrieve the firmware/software version number. Compare this version against any known affected version ranges provided by the vendor.Affected if The installed version falls within the vendor-specified affected version range.
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Verify IEC 60870-5-104 BCI configuration statusAccess the RTU500 configuration settings and locate the IEC 60870-5-104 protocol configuration. Check whether bidirectional mode (often labeled as BCI, bidirectional, or similar) is enabled or disabled.Affected if IEC 60870-5-104 bidirectional mode is enabled - this is the required condition for the vulnerability to be exploitable.
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Monitor for DoS symptoms or service disruptionsReview RTU500 system logs, event logs, or network monitoring data for unexplained crashes, service restarts, or NULL pointer dereference error messages occurring after periods of unusual IEC 60870-5-104 traffic patterns.Affected if The system exhibits repeated crashes or DoS conditions correlated with IEC 60870-5-104 bidirectional mode traffic.
A user is affected if they are running a vulnerable RTU500 version with IEC 60870-5-104 bidirectional mode enabled and experiencing NULL pointer dereference crashes from sustained malformed message sequences.
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 dataIf bidirectional mode (BCI) is not required, disable it to eliminate the attack surface. Otherwise, contact the vendor for patches and monitor for updates. Implement network segmentation and access controls to limit exposure to unauthenticated network attackers.
- Consultation4.0 h
- Implementation8.0 h
- Testing6.0 h
- Review / QA4.0 h
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Free · runs locallyCheck whether your project pulls in CVE-2026-8479 — 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-2026-8479 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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