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CVE-2026-63831

HIGH
High
EPSS 0.25%Patch availableJul 21, 2026

Linux mac802154 llsec in-place crypto corrupts shared skb, causing UAF and kernel crashes.

common questions

Is CVE-2026-63831 being exploited?

Not confirmed. CVE-2026-63831 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 0.25% probability of exploitation in the next 30 days.

How severe is CVE-2026-63831?

CVE-2026-63831 is rated High. 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-2026-63831?

Yes. A fix has been recorded for CVE-2026-63831. The vendor advisory is the authority on the exact fixed version — apply it from there rather than from a summary.

What does CVE-2026-63831 affect?

CVE-2026-63831 affects Linux kernel (mac802154 llsec), Devices using IEEE 802.15.4 (IoT gateways, embedded devices), Any system with mac802154/llsec enabled. Confirm the exact affected versions against the vendor advisory before deciding you are exposed.

What should I do about CVE-2026-63831?

Apply vendor/kernel security updates or backport patch; disable mac802154/llsec if not needed.

Exploitation status reflects CISA's KEV catalog as we last synced it. Check the catalog directly.

executive summary
technical analysis
affected
Linux kernel (mac802154 llsec)Devices using IEEE 802.15.4 (IoT gateways, embedded devices)Any system with mac802154/llsec enabled
impact

Remote 802.15.4 frames can trigger in-kernel memory corruption/use-after-free, causing crashes and enabling potential privilege escalation or remote code execution.

action required

Immediate action required

affected versions
Linux Linux
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < 3a2b378b3a9ca75d3518d879148d2ad25b5714a9
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < 7a831bcd0486788283ef35e396d4282ee01bb0d5
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < ff976ef7c39199ebff33c18034636595016db9f0
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < e28e7fd34c449028325322a3f5127b92594b7396
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < 993fd674fe85d114e6a8d3963033d4fbbc2170a8
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < bd968bdd568beacfdf98ec537a87527e85f1d0cf
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < 86d531337ea1ba02d9f2bc830d07c683d9bfaade
  • affected>= 03556e4d0dbbbf4af9df76f4a3839c86f6afb015 and < 84a04eb5b210643bd67aab81ff805d32f62aa865
  • affected3.16
vendor says fixed in< 3.16, >= 5.10.260 and <= 5.10.*, >= 5.15.211 and <= 5.15.*, >= 6.1.177 and <= 6.1.*, >= 6.6.144 and <= 6.6.*, >= 6.12.95 and <= 6.12.*, >= 6.18.38 and <= 6.18.*, >= 7.1.3 and <= 7.1.*, >= 7.2 and <= *

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.

how to fix
Remediation steps are tailored for users whose stack is affected. Add this technology to your stack to see the fix checklist.
references
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