Systems
CVE-2026-15390
U-Boot IP defragmentation flaw permits remote RCE via crafted fragmented IP packets.
Major vulnerability. U-Boot is a widely used bootloader across embedded, network and industrial devices; bootloader RCE can compromise fleets and persist across reboots.
- CVSS
- 9.0Criticalscored by the publisher (CNA)
- Exploited in the wild
- Not knownnot in CISA KEV as of our last sync
- EPSS
- 0.19%chance of exploitation in the next 30 daystop 91% of scored CVEsFIRST score of 12 Nov 2026
- Fix
- Patch availablesee the advisories in the references
- Published
- 29 Sept 2026analysed here 29 Sept 2026
Summary
Impact
Remote arbitrary code execution by sending duplicated last-fragment IP packets during IP reassembly, enabling persistent device compromise.
Triage
- Attack surface
- Server-side
- Exploitable
- At runtime
- Attack vector
- adjacent network
- Can a WAF block it?
- No. See why
The summary, impact and action text on this page are written by our AI analysis pipeline, or taken from the NVD description when a CVE was imported from NVD. They are not the vendor's wording: check them against the sources. A longer AI executive summary and technical analysis are generated for signed-in accounts on the Max plan.
Affected products
| Product | Affected versions | Vendor says fixed in |
|---|---|---|
| DENX Software Engineering Das U-Boot | >= 2009.08 and <= 2026.07Vendor says fixed in: not stated |
As published in the CVE Program record. A version outside these ranges is not a statement that it is unaffected — vendors sometimes understate a range, and distribution-backported builds carry upstream numbers that do not reflect what was patched into them.
Products named in our analysis
- Das U-Boot bootloader (embedded devices)
- Routers
- IoT devices
- Industrial/OT devices using U-Boot
Fix and mitigation
Action required
Immediate action required
WAF and other mitigations
Can a WAF block it? No. The attack uses crafted fragmented IP packets sent over the network, not HTTP requests, so a web application firewall cannot filter these packets.
Also consider: patch
Based on an AI reading of the CVE description, and no vendor rule found yet. We check Cloudflare, AWS, Google Cloud Armor and Azure; for Akamai, Imperva, Fastly, F5, ask your vendor.
Remediation steps (AI-written)
Step-by-step remediation is generated for accounts on the Max plan, for CVEs that match a technology in their stack. Add this technology to your stack to see the fix checklist.
Exploitation evidence
- CISA KEV catalog
- Not listed as of our last sync.
- Public exploit code
- None on record in Exploit-DB, Metasploit, Nuclei templates or PoC-in-GitHub.
- CISA SSVC
- exploitation none, automatable no, technical impact totalAssessed by CISA 29 Sept 2026 (SSVC 2.0.3). Exploitation is none, poc (public proof of concept) or active.
Timeline
- 29 Sept 2026Published
- 29 Sept 2026CISA SSVC assessment: exploitation nonesame day later
- 29 Sept 2026CVE record last updatedsame day later
- 29 Sept 2026Analysed by vulneraibility.comsame day later
Common questions
Is CVE-2026-15390 being exploited?
Not confirmed. CVE-2026-15390 does not appear in CISA's Known Exploited Vulnerabilities catalog, which records only exploitation that has been observed and reported publicly. That is evidence of absence of a report, not evidence the flaw is unattacked. EPSS currently estimates a 0.19% probability of exploitation in the next 30 days.
How severe is CVE-2026-15390?
CVE-2026-15390 is rated Critical with a CVSS score of 9.0. Severity describes how bad exploitation would be, not how likely it is: pair it with exploitation evidence before deciding what to patch first.
Is there a patch for CVE-2026-15390?
Yes. A fix has been recorded for CVE-2026-15390. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.
What does CVE-2026-15390 affect?
CVE-2026-15390 affects Das U-Boot bootloader (embedded devices), Routers, IoT devices, Industrial/OT devices using U-Boot. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.
What should I do about CVE-2026-15390?
Upgrade U-Boot to 2026.07 or apply vendor patch; block/inspect fragmented IP traffic.
Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.
References
2 references in the CVE record, grouped by the tags the record gives them.
Advisories (1)
- cert.pl /en/posts/2026/09/CVE-2026-15390
Patches (1)
- source.denx.de /u-boot/u-boot/-/commit/b1aec609bb5e0d08c25c888c91935287ab4ee5fa
Where the data on this page comes from
- CVE List (CVE.org): description, affected versions, references; CVE Terms of Use
- NVD: CVSS and CPE data
- CISA Vulnrichment (ADP): SSVC decision points
- FIRST EPSS: exploit probability and percentile
Summary, impact and triage tags: written by our AI analysis pipeline from the sources above. Check them against the sources.
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