146 lines
7.5 KiB
JSON
146 lines
7.5 KiB
JSON
{
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"dataType": "CVE_RECORD",
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"dataVersion": "5.2",
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"cveMetadata": {
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"cveId": "CVE-2026-79976",
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"assignerOrgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
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"state": "PUBLISHED",
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"assignerShortName": "zephyr",
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"dateReserved": "2026-08-25T16:06:27.086Z",
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"datePublished": "2026-10-21T18:19:34.519Z",
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"dateUpdated": "2026-11-04T05:01:22.440Z"
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},
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"containers": {
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"cna": {
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"providerMetadata": {
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"orgId": "e2e69745-5e70-4e92-8431-deb5529a81ad",
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"shortName": "zephyr",
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"dateUpdated": "2026-11-04T05:01:22.440Z"
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},
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"title": "NULL pointer dereference in the MCTP I2C+GPIO target binding triggerable by a peer I2C controller",
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"descriptions": [
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{
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"lang": "en",
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"value": "The MCTP-over-I2C+GPIO target binding in subsys/pmci/mctp/mctp_i2c_gpio_target.c emulates a small pseudo-register file, where the bus controller first writes a register number and then writes or reads payload bytes. The selected register (b->reg_addr) and the data-phase flag (b->rxtx) were never cleared when the controller issued an I2C STOP, so after a completed transfer the target still had a data register selected while the packet buffer that register refers to had already been consumed and set to NULL by mctp_i2c_gpio_target_stop().\n\nA controller on the bus can re-enter the same branch of mctp_i2c_gpio_target_stop() with a NULL buffer using two ordinary transactions and no authentication: first a normal packet write to MCTP_I2C_GPIO_RX_MSG_ADDR followed by STOP (which delivers and frees b->rx_pkt), then a bare read transaction followed by STOP. The failing read_requested() call leaves the stale state untouched and the I2C driver still delivers the STOP callback, which then calls mctp_bus_rx() with a NULL packet. The symmetric case exists on the transmit side, where the stale MCTP_I2C_GPIO_TX_MSG_ADDR selection dereferences b->tx_pkt->end after b->tx_pkt has been cleared and additionally signals b->tx_complete a second time, causing the next outbound packet to be dropped.\n\nThe dereference happens in the I2C target interrupt handler, so on any target that traps accesses to address 0 the result is a fatal exception and a device reset or halt — a denial of service inflicted by any device able to act as controller on the shared management bus (for example compromised firmware on a peer MCTP endpoint or on the BMC). On parts where address 0 is readable, the impact degrades to a malformed packet buffer being handed to the MCTP stack and lost transmit packets. No attacker-controlled value is written and no confidentiality or integrity boundary is crossed.\n\nThe fix resets b->reg_addr to MCTP_I2C_GPIO_INVALID_ADDR and clears b->rxtx at every STOP, so a new register must be selected before any data phase can run again. Only builds that opt into the experimental CONFIG_MCTP subsystem with CONFIG_MCTP_I2C_GPIO_TARGET=y are affected."
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}
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],
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"affected": [
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{
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"vendor": "zephyrproject",
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"product": "zephyr",
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"collectionURL": "https://github.com/zephyrproject-rtos/zephyr",
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"packageName": "zephyr",
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"defaultStatus": "unaffected",
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"programFiles": [
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"subsys/pmci/mctp/mctp_i2c_gpio_target.c"
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],
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"programRoutines": [
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{
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"name": "mctp_i2c_gpio_target_read_processed"
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},
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{
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"name": "mctp_i2c_gpio_target_read_requested"
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},
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{
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"name": "mctp_i2c_gpio_target_stop"
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}
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],
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"versions": [
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{
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"version": "4.3.0",
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"status": "affected",
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"versionType": "semver",
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"lessThan": "4.3.2"
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},
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{
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"version": "4.4.0",
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"status": "affected",
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"versionType": "semver",
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"lessThan": "4.5.0"
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}
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]
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}
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],
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"references": [
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{
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"url": "https://github.com/zephyrproject-rtos/zephyr/commit/60f7fee438504de29f2473d7a8d0535235b983ef",
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"name": "Fix commit 60f7fee43850",
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"tags": [
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"patch"
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]
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},
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{
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"url": "https://github.com/zephyrproject-rtos/zephyr/commit/a097178023785f3bc0a925ac489e490521ca84ea",
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"name": "Fix commit a09717802378",
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"tags": [
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"patch"
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]
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},
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{
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"url": "https://github.com/zephyrproject-rtos/zephyr/security/advisories/GHSA-76fx-m4mf-24gq",
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"name": "GHSA-76fx-m4mf-24gq"
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}
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],
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"metrics": [
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{
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"format": "CVSS",
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"cvssV3_1": {
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"version": "3.1",
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"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:H",
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"baseScore": 7.1,
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"baseSeverity": "HIGH"
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}
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}
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],
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"problemTypes": [
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{
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"descriptions": [
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{
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"lang": "en",
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"description": "memory-safety",
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"cweId": "CWE-476",
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"type": "CWE"
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}
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]
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}
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],
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"x_generator": {
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"engine": "cvelib 1.8.0"
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}
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},
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"adp": [
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{
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"metrics": [
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{
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"other": {
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"type": "ssvc",
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"content": {
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"timestamp": "2026-10-23T20:43:08.859407Z",
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"id": "CVE-2026-79976",
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"options": [
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{
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"Exploitation": "none"
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},
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{
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"Automatable": "no"
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},
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{
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"Technical Impact": "partial"
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}
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],
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"role": "CISA Coordinator",
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"version": "2.0.3"
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}
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}
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}
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],
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"title": "CISA ADP Vulnrichment",
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"providerMetadata": {
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"orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
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"shortName": "CISA-ADP",
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"dateUpdated": "2026-10-23T21:27:29.128Z"
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}
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}
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]
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}
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} |