{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-74733","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-15T05:44:03.930Z","datePublished":"2026-08-22T15:33:21.579Z","dateUpdated":"2026-08-25T05:42:11.965Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-25T05:42:11.965Z"},"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."}],"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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpio/gpio-pca953x.c"],"versions":[{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","lessThan":"e6a2f5f845f50b0c4299bace5111f56d3390a090","status":"affected","versionType":"git"},{"version":"bfc6444b57dc7186b6acc964705d7516cbaf3904","lessThan":"9dc325327babe7f159e84cbe9380a45342da0585","status":"affected","versionType":"git"},{"version":"58a5c93bd1a6e949267400080f07e57ffe05ec34","status":"affected","versionType":"git"},{"version":"e2ecdddca80dd845df42376e4b0197fe97018ba2","status":"affected","versionType":"git"},{"version":"de7cffa53149c7b48bd1bb29b02390c9f05b7f41","status":"affected","versionType":"git"},{"version":"6.1.101","lessThan":"6.2","status":"affected","versionType":"semver"},{"version":"6.6.42","lessThan":"6.7","status":"affected","versionType":"semver"},{"version":"6.9.11","lessThan":"6.10","status":"affected","versionType":"semver"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/gpio/gpio-pca953x.c"],"versions":[{"version":"6.10","status":"affected"},{"version":"0","lessThan":"6.10","status":"unaffected","versionType":"semver"},{"version":"7.1.9","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","lessThanOrEqual":"*","status":"unaffected","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"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":"6.1.101"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.6.42"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.9.11"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/e6a2f5f845f50b0c4299bace5111f56d3390a090"},{"url":"https://git.kernel.org/stable/c/9dc325327babe7f159e84cbe9380a45342da0585"}],"title":"gpio: pca953x: fix pca953x_irq_bus_sync_unlock regmap lock","x_generator":{"engine":"bippy-1.2.0"}}}}