{"id":"CVE-2025-38480","state":"PUBLISHED","title":"comedi: Fix use of uninitialized data in insn_rw_emulate_bits()","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: Fix use of uninitialized data in insn_rw_emulate_bits()\n\nFor Comedi `INSN_READ` and `INSN_WRITE` instructions on \"digital\"\nsubdevices (subdevice types `COMEDI_SUBD_DI`, `COMEDI_SUBD_DO`, and\n`COMEDI_SUBD_DIO`), it is common for the subdevice driver not to have\n`insn_read` and `insn_write` handler functions, but to have an\n`insn_bits` handler function for handling Comedi `INSN_BITS`\ninstructions.  In that case, the subdevice's `insn_read` and/or\n`insn_write` function handler pointers are set to point to the\n`insn_rw_emulate_bits()` function by `__comedi_device_postconfig()`.\n\nFor `INSN_WRITE`, `insn_rw_emulate_bits()` currently assumes that the\nsupplied `data[0]` value is a valid copy from user memory.  It will at\nleast exist because `do_insnlist_ioctl()` and `do_insn_ioctl()` in\n\"comedi_fops.c\" ensure at lease `MIN_SAMPLES` (16) elements are\nallocated.  However, if `insn->n` is 0 (which is allowable for\n`INSN_READ` and `INSN_WRITE` instructions, then `data[0]` may contain\nuninitialized data, and certainly contains invalid data, possibly from a\ndifferent instruction in the array of instructions handled by\n`do_insnlist_ioctl()`.  This will result in an incorrect value being\nwritten to the digital output channel (or to the digital input/output\nchannel if configured as an output), and may be reflected in the\ninternal saved state of the channel.\n\nFix it by returning 0 early if `insn->n` is 0, before reaching the code\nthat accesses `data[0]`.  Previously, the function always returned 1 on\nsuccess, but it is supposed to be the number of data samples actually\nread or written up to `insn->n`, which is 0 in this case.","publishedAt":"2025-07-28T11:21:45.142Z","updatedAt":"2026-05-11T21:28:49.584Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"4c2981bf30401adfcdbfece4ab6f411f7c5875a1","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"16256d7efcf7acc9f39abe21522c4c6b77f67c00","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"c53570e62b5b28bdb56bb563190227f8307817a5","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"3050d197d6bc9ef128944a70210f42d2430b3000","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"10f9024a8c824a41827fff1fefefb314c98e2c88","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"2af1e7d389c2619219171d23f5b96dbcbb7f9656","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"e9cb26291d009243a4478a7ffb37b3a9175bfce9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/comedi/drivers.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","versionType":"semver"},{"version":"5.4.297","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.241","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.190","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.147","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.100","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.40","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.15.8","status":"unaffected","lessThanOrEqual":"6.15.*","versionType":"semver"},{"version":"6.16","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/comedi/drivers.c"]}],"references":["https://git.kernel.org/stable/c/4c2981bf30401adfcdbfece4ab6f411f7c5875a1","https://git.kernel.org/stable/c/16256d7efcf7acc9f39abe21522c4c6b77f67c00","https://git.kernel.org/stable/c/c53570e62b5b28bdb56bb563190227f8307817a5","https://git.kernel.org/stable/c/3050d197d6bc9ef128944a70210f42d2430b3000","https://git.kernel.org/stable/c/10f9024a8c824a41827fff1fefefb314c98e2c88","https://git.kernel.org/stable/c/2af1e7d389c2619219171d23f5b96dbcbb7f9656","https://git.kernel.org/stable/c/3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870","https://git.kernel.org/stable/c/e9cb26291d009243a4478a7ffb37b3a9175bfce9","https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html","https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:09.358Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/38xxx/CVE-2025-38480.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-38480","state":"PUBLISHED","datePublished":"2025-07-28T11:21:45.142Z","dateUpdated":"2026-05-11T21:28:49.584Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-04-16T04:51:24.021Z"},"containers":{"cna":{"title":"comedi: Fix use of uninitialized data in insn_rw_emulate_bits()","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncomedi: Fix use of uninitialized data in insn_rw_emulate_bits()\n\nFor Comedi `INSN_READ` and `INSN_WRITE` instructions on \"digital\"\nsubdevices (subdevice types `COMEDI_SUBD_DI`, `COMEDI_SUBD_DO`, and\n`COMEDI_SUBD_DIO`), it is common for the subdevice driver not to have\n`insn_read` and `insn_write` handler functions, but to have an\n`insn_bits` handler function for handling Comedi `INSN_BITS`\ninstructions.  In that case, the subdevice's `insn_read` and/or\n`insn_write` function handler pointers are set to point to the\n`insn_rw_emulate_bits()` function by `__comedi_device_postconfig()`.\n\nFor `INSN_WRITE`, `insn_rw_emulate_bits()` currently assumes that the\nsupplied `data[0]` value is a valid copy from user memory.  It will at\nleast exist because `do_insnlist_ioctl()` and `do_insn_ioctl()` in\n\"comedi_fops.c\" ensure at lease `MIN_SAMPLES` (16) elements are\nallocated.  However, if `insn->n` is 0 (which is allowable for\n`INSN_READ` and `INSN_WRITE` instructions, then `data[0]` may contain\nuninitialized data, and certainly contains invalid data, possibly from a\ndifferent instruction in the array of instructions handled by\n`do_insnlist_ioctl()`.  This will result in an incorrect value being\nwritten to the digital output channel (or to the digital input/output\nchannel if configured as an output), and may be reflected in the\ninternal saved state of the channel.\n\nFix it by returning 0 early if `insn->n` is 0, before reaching the code\nthat accesses `data[0]`.  Previously, the function always returned 1 on\nsuccess, but it is supposed to be the number of data samples actually\nread or written up to `insn->n`, which is 0 in this case."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"4c2981bf30401adfcdbfece4ab6f411f7c5875a1","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"16256d7efcf7acc9f39abe21522c4c6b77f67c00","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"c53570e62b5b28bdb56bb563190227f8307817a5","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"3050d197d6bc9ef128944a70210f42d2430b3000","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"10f9024a8c824a41827fff1fefefb314c98e2c88","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"2af1e7d389c2619219171d23f5b96dbcbb7f9656","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870","versionType":"git"},{"version":"ed9eccbe8970f6eedc1b978c157caf1251a896d4","status":"affected","lessThan":"e9cb26291d009243a4478a7ffb37b3a9175bfce9","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/comedi/drivers.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"2.6.29","status":"affected"},{"version":"0","status":"unaffected","lessThan":"2.6.29","versionType":"semver"},{"version":"5.4.297","status":"unaffected","lessThanOrEqual":"5.4.*","versionType":"semver"},{"version":"5.10.241","status":"unaffected","lessThanOrEqual":"5.10.*","versionType":"semver"},{"version":"5.15.190","status":"unaffected","lessThanOrEqual":"5.15.*","versionType":"semver"},{"version":"6.1.147","status":"unaffected","lessThanOrEqual":"6.1.*","versionType":"semver"},{"version":"6.6.100","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.40","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.15.8","status":"unaffected","lessThanOrEqual":"6.15.*","versionType":"semver"},{"version":"6.16","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/comedi/drivers.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/4c2981bf30401adfcdbfece4ab6f411f7c5875a1"},{"url":"https://git.kernel.org/stable/c/16256d7efcf7acc9f39abe21522c4c6b77f67c00"},{"url":"https://git.kernel.org/stable/c/c53570e62b5b28bdb56bb563190227f8307817a5"},{"url":"https://git.kernel.org/stable/c/3050d197d6bc9ef128944a70210f42d2430b3000"},{"url":"https://git.kernel.org/stable/c/10f9024a8c824a41827fff1fefefb314c98e2c88"},{"url":"https://git.kernel.org/stable/c/2af1e7d389c2619219171d23f5b96dbcbb7f9656"},{"url":"https://git.kernel.org/stable/c/3ab55ffaaf75d0c7b68e332c1cdcc1b0e0044870"},{"url":"https://git.kernel.org/stable/c/e9cb26291d009243a4478a7ffb37b3a9175bfce9"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:28:49.584Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.4.297"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.10.241"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"5.15.190"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.1.147"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.6.100"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.12.40"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.15.8"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"2.6.29","versionEndExcluding":"6.16"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html"}],"providerMetadata":{"shortName":"CVE","orgId":"af854a3a-2127-422b-91ae-364da2661108","dateUpdated":"2025-11-03T17:38:48.508Z"}}]}}}