CVE-2026-10678
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NULL-pointer / out-of-bounds write in Zephyr MCTP I2C+GPIO target binding driven by an unauthenticated I2C controller
rank 22 = 0 + 20 + 0 + 2 + 0
rank@v1 · backlog
Someone is already using it
CISA KEV catalog · public proof-of-concept · FIRST EPSS
EPSS 0.00390 · without this subject the record ranks 22
What it costs you if it fires
NVD CVSS base score, then the CNA's own
CVSS 8.1, from the CNA · without this subject the record ranks 2
It is getting worse, not staying still
FIRST EPSS series, rescorings and bad loads removed
no persisting rise in 365 days · without this subject the record ranks 22
How much of the world it touches
NVD CPE configurations
1 product in the CPE ranges · without this subject the record ranks 20
Someone else already set the date
CISA KEV remediation due date
no CISA due date · without this subject the record ranks 22
$17,200 = $4.99M incident cost x 0.8814887365328109 exposure x 0.0039 likelihood
udv@v1 · unaudited · wrong for you until you say what you run
$4.99M is the cost of a breach that happened, from IBM Cost of a Data Breach Report 2026, global average. It is not the value of any asset of yours. That average already covers breaches of every severity, so scaling it by exposure understates a partial-impact record. That is an assumption, not a measurement. Your own asset value goes in the decision record.
Hindsight · the state
Foresight · where to check next
No weakness class or product neighbourhood is held for this record, so this index cannot name anywhere to check next. That is an absence in the record, not a finding about the software.
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Harm, if it fires from the vector and the weakness
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CISA KEV & Federal Remediation Deadline from the record and CISA
The fix, and how long it's been waiting.
Exploit Status & Known PoCs a ladder, not a score
Current rung: Nothing observed in held sources.
- RUNG 1Nothing observed in held sources
- RUNG 2Proof-of-concept published
- RUNG 3Exploited in the wild · CISA KEV listed
- RUNG 4Ransomware campaign use known
A rung lights from a row in the index, never from an assessment. "Held sources" is the true scope of the claim: this index reads the CVE record, NVD, CISA KEV, FIRST's EPSS and public proof-of-concept repositories, and it does not observe attacks.
Attack path
What it is stated by the CNA
The MCTP-over-I2C+GPIO target binding in Zephyr (subsys/pmci/mctp/mctp_i2c_gpio_target.c) processes pseudo-register writes from an I2C bus master byte-by-byte in mctp_i2c_gpio_target_write_received() without validating the order or the receive buffer. In the affected versions the MCTP_I2C_GPIO_RX_MSG_ADDR (data) handler dereferences and writes through b->rx_pkt without checking that the receive buffer was allocated: a controller that selects the data register and writes a byte without first sending the length register (which is what allocates the buffer) causes a write of an attacker-chosen byte through a NULL/unallocated mctp_pktbuf pointer (i.e. receipt
Read the rest of the CNA's description
into a small attacker-advanceable offset above address 0), producing memory corruption or a hard fault. The same handler also performs a write-then-check bounds test, allowing a one-byte heap overflow at data[255] when more than 255 data bytes are sent. Because the I2C target callback is invoked with raw bytes supplied by whatever device is the bus master and the binding performs no authentication, a malicious or malfunctioning controller on the bus can trigger these without any prior protocol state, leading to memory corruption and/or denial of service on the target device. The vulnerable code was introduced when the I2C+GPIO target binding was added and shipped in Zephyr v4.3.0 and v4.4.0. The fix defers allocation to the first data byte with a NULL check, treats a missing length as a zero-sized packet rejected by libmctp, and moves the bounds check before the store.
NVD's analysis a second authority
- weakness
- CWE-476; CWE-787
- affected versions
- zephyrproject zephyr >= 4.3.0 <= 4.4.1
- also scored by
- [email protected] 8.1 CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:H
check it yourself github.com github.com receipt
Movement the material steps
Show all 2 observations
2 observations held. A highlighted step crossed a promotion threshold. A step marked with a scoring model moved because the instrument was replaced, not because the vulnerability changed. receipt
The full biography
The record had been public for 1 month when this index was last written.
Siblings and hubs
Records related to this one
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Its defect family
zephyrproject zephyr
Of the 10 records in this family, this is the only one whose title names out-of-bounds write mctp.
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Family membership: held values
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What usually comes next
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