{"id":"CVE-2026-74733","state":"PUBLISHED","title":"gpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ngpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock\n\nLocking is disabled in the regmap config as this driver uses its own\nlock. This means that all calls to regmap functions (read or write) must\nhold the i2c_lock. The function pca953x_irq_bus_sync_unlock() did not do\nthis, and it was therefore possible that multiple threads could cause an\nincorrect register to be read/written.\n\nA previous patch partly fixed this, but only protected the write to the\ninterrupt mask register, and not the read from the direction register.","publishedAt":"2026-08-22T15:33:21.579Z","updatedAt":"2026-10-30T12:30:25.982Z","severity":{"score":7.8,"label":"High","version":"3.1","vector":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","source":"Linux"},"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"58a5c93bd1a6e949267400080f07e57ffe05ec34","status":"affected","lessThan":"58ed56c093a857c19f04cf3db1f02d2e793aec88","versionType":"git"},{"version":"e2ecdddca80dd845df42376e4b0197fe97018ba2","status":"affected","lessThan":"5d05c4252c09ce10624be2197853c80bf87424e4","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"41255e64eb9dd87b0b8675f4e47a9c67bcef6e39","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"bf3f37c2d40b51deb79aea910f28999d7c8c6b5a","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"e6a2f5f845f50b0c4299bace5111f56d3390a090","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"9dc325327babe7f159e84cbe9380a45342da0585","versionType":"git"},{"version":"de7cffa53149c7b48bd1bb29b02390c9f05b7f41","status":"affected","versionType":"git"},{"version":"6.1.101","status":"affected","lessThan":"6.1.191","versionType":"semver"},{"version":"6.6.42","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.9.11","status":"affected","lessThan":"6.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpio/gpio-pca953x.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.9","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpio/gpio-pca953x.c"]}],"references":["https://git.kernel.org/stable/c/58ed56c093a857c19f04cf3db1f02d2e793aec88","https://git.kernel.org/stable/c/5d05c4252c09ce10624be2197853c80bf87424e4","https://git.kernel.org/stable/c/41255e64eb9dd87b0b8675f4e47a9c67bcef6e39","https://git.kernel.org/stable/c/bf3f37c2d40b51deb79aea910f28999d7c8c6b5a","https://git.kernel.org/stable/c/e6a2f5f845f50b0c4299bace5111f56d3390a090","https://git.kernel.org/stable/c/9dc325327babe7f159e84cbe9380a45342da0585"],"weaknesses":[],"ingestedAt":"2026-10-30T12:48:04.825Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2026/74xxx/CVE-2026-74733.json","commit":"1f312381e38164a43607eebab851b151dd16861e","baselineCommit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74733","state":"PUBLISHED","datePublished":"2026-08-22T15:33:21.579Z","dateUpdated":"2026-10-30T12:30:25.982Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2026-08-15T05:44:03.930Z"},"containers":{"cna":{"title":"gpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ngpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock\n\nLocking is disabled in the regmap config as this driver uses its own\nlock. This means that all calls to regmap functions (read or write) must\nhold the i2c_lock. The function pca953x_irq_bus_sync_unlock() did not do\nthis, and it was therefore possible that multiple threads could cause an\nincorrect register to be read/written.\n\nA previous patch partly fixed this, but only protected the write to the\ninterrupt mask register, and not the read from the direction register."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"58a5c93bd1a6e949267400080f07e57ffe05ec34","status":"affected","lessThan":"58ed56c093a857c19f04cf3db1f02d2e793aec88","versionType":"git"},{"version":"e2ecdddca80dd845df42376e4b0197fe97018ba2","status":"affected","lessThan":"5d05c4252c09ce10624be2197853c80bf87424e4","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"41255e64eb9dd87b0b8675f4e47a9c67bcef6e39","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"bf3f37c2d40b51deb79aea910f28999d7c8c6b5a","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"e6a2f5f845f50b0c4299bace5111f56d3390a090","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","status":"affected","lessThan":"9dc325327babe7f159e84cbe9380a45342da0585","versionType":"git"},{"version":"de7cffa53149c7b48bd1bb29b02390c9f05b7f41","status":"affected","versionType":"git"},{"version":"6.1.101","status":"affected","lessThan":"6.1.191","versionType":"semver"},{"version":"6.6.42","status":"affected","lessThan":"6.6.160","versionType":"semver"},{"version":"6.9.11","status":"affected","lessThan":"6.10","versionType":"semver"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpio/gpio-pca953x.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.10","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.10","versionType":"semver"},{"version":"6.1.191","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.160","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.114","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.18.57","status":"unaffected","lessThanOrEqual":"6.18.*","versionType":"semver"},{"version":"7.1.9","status":"unaffected","lessThanOrEqual":"7.1.*","versionType":"semver"},{"version":"7.2","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpio/gpio-pca953x.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/58ed56c093a857c19f04cf3db1f02d2e793aec88"},{"url":"https://git.kernel.org/stable/c/5d05c4252c09ce10624be2197853c80bf87424e4"},{"url":"https://git.kernel.org/stable/c/41255e64eb9dd87b0b8675f4e47a9c67bcef6e39"},{"url":"https://git.kernel.org/stable/c/bf3f37c2d40b51deb79aea910f28999d7c8c6b5a"},{"url":"https://git.kernel.org/stable/c/e6a2f5f845f50b0c4299bace5111f56d3390a090"},{"url":"https://git.kernel.org/stable/c/9dc325327babe7f159e84cbe9380a45342da0585"}],"metrics":[{"cvssV3_1":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H","baseScore":7.8,"baseSeverity":"HIGH"},"scenarios":[{"lang":"en","value":"AV:L - The vulnerable pca953x_irq_bus_sync_unlock() path is reached only through local kernel interfaces—GPIO chardev ioctls (GPIO_V2_GET_LINE_IOCTL, GPIO_V2_LINE_SET_CONFIG_IOCTL, GPIO_V2_LINE_SET_VALUES_IOCTL), legacy sysfs GPIO, or concurrent in-kernel GPIO/IRQ ops—not via any network or physical bus-facing attack surface.\nAC:L - An attacker drives both racing sides directly: one thread loops IRQ edge-detection setup/teardown (request_irq → irq_bus_sync_unlock) while another hammers GPIO value/direction writes holding i2c_lock; the original report reproduced the race ~1 in 1000 boots, so deliberate concurrency wins reliably.\nPR:L - Exploitation requires an open file descriptor on /dev/gpiochipN or sysfs GPIO access; on embedded, industrial, medical, and automotive boards using pca953x expanders, udev routinely grants gpio group membership to unprivileged local users.\nUI:N - No victim interaction is required—the attacker performs all GPIO ioctl and IRQ configuration steps in its own threads without needing another user to mount, open, or configure devices.\nS:U - Corruption is confined to the kernel and the same on-board I2C GPIO expander; it does not cross VM, container, IOMMU, or other security-boundary scopes into a different authority.\nC:H - With regmap disable_locking=true, the unprotected pca953x_read_regs() direction read races locked regmap paths, corrupting the maple regcache and returning data from the wrong register—yielding kernel heap UAF read and unintended register-state disclosure.\nI:H - Racing regmap transactions write interrupt-latch/direction data into wrong expander registers (documented output-register corruption), arbitrarily toggling safety-critical GPIO outputs; concurrent unsynchronized regcache writes provide a heap corruption/write primitive.\nA:H - Concurrent regcache maple-tree corruption from unsynchronized regmap access can trigger kernel oops/panic via double-free; miswritten interrupt masks or direction registers can wedge expander IRQ handling and GPIO consumers in a persistent denial-of-service."}]}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-10-30T12:30:25.982Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.1.101","versionEndExcluding":"6.1.191"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.42","versionEndExcluding":"6.6.160"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.12.114"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"6.18.57"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.1.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.10","versionEndExcluding":"7.2"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9.11"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CISA ADP Vulnrichment","metrics":[{"other":{"type":"ssvc","content":{"id":"CVE-2026-74733","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"total"}],"version":"2.0.3","timestamp":"2026-10-16T19:15:53.820928Z"}}}],"providerMetadata":{"shortName":"CISA-ADP","orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","dateUpdated":"2026-10-16T19:16:12.549Z"}}]}}}