{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2023-53491", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2025-10-01T11:39:39.403Z", "datePublished": "2025-10-01T11:45:43.101Z", "dateUpdated": "2026-08-05T09:14:23.246Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T09:14:23.246Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nstart_kernel: Add __no_stack_protector function attribute\n\nBack during the discussion of\ncommit a9a3ed1eff36 (\"x86: Fix early boot crash on gcc-10, third try\")\nwe discussed the need for a function attribute to control the omission\nof stack protectors on a per-function basis; at the time Clang had\nsupport for no_stack_protector but GCC did not. This was fixed in\ngcc-11. Now that the function attribute is available, let's start using\nit.\n\nCallers of boot_init_stack_canary need to use this function attribute\nunless they're compiled with -fno-stack-protector, otherwise the canary\nstored in the stack slot of the caller will differ upon the call to\nboot_init_stack_canary. This will lead to a call to __stack_chk_fail()\nthen panic." } ], "metrics": [ { "cvssV3_1": { "version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H", "baseScore": 7.5, "baseSeverity": "HIGH" }, "scenarios": [ { "lang": "en", "value": "AV:N - There is no network-reachable path to this code — `start_kernel()` and powerpc `start_secondary()` are kernel-initialization and CPU-bring-up entry points invoked from architecture assembly (`head_64.S`, `head_44x.S`, `head_85xx.S`) and from `__cpu_up()` during hotplug/resume, all of which are local to the machine. The vulnerable component is therefore only reachable via local system context (boot, CPU hotplug, suspend/resume).\nAC:L - On a kernel built with `CONFIG_STACKPROTECTOR=y` and a toolchain that instruments these functions, the stale-canary comparison mismatches deterministically on every boot and every secondary-CPU bring-up — there is no race, no memory-layout dependency, and no timing window to win. The failure reproduces reliably and at will, so no condition beyond the attacker's control gates it.\nPR:N - The panic in `start_kernel()` occurs during kernel initialization, before `init(1)` and before any user account, credential check, or namespace exists; the `start_secondary()` path is likewise entered from the secondary-CPU assembly stub with no privilege gate. No authentication or privilege of any kind is involved in reaching the faulty canary check.\nUI:N - No victim action is needed — the condition is hit automatically as part of normal boot and CPU bring-up. Nothing must be mounted, opened, or clicked.\nS:U - The `__stack_chk_fail()` → `panic()` sequence is entirely contained within the kernel's own security authority, affecting only the kernel that executed it. No VM, IOMMU, or sandbox boundary is crossed.\nC:N - `__stack_chk_fail()` is a fail-stop check: it halts the system rather than reading or exposing memory, and no out-of-bounds read, uninitialized data, or attacker-retrievable kernel state is produced. Per the pure-crash guidance, there is no information disclosure.\nI:N - Nothing is written out of bounds and no object is corrupted — the canary in the caller's frame is intact; the comparison is a false positive caused by the canary *source* changing underneath it. There is no write primitive and no control-flow hijack potential.\nA:H - The outcome is `panic(\"stack-protector: Kernel stack is corrupted in: start_kernel\")`, i.e. an unbootable system, or a panic during secondary-CPU bring-up via `start_secondary()` on hotplug/resume. This is total, unrecoverable loss of availability for the affected machine." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/powerpc/kernel/smp.c", "include/linux/compiler_attributes.h", "init/main.c" ], "versions": [ { "version": "420594296838fdc9a674470d710cda7d1487f9f4", "lessThan": "25e73018b4093e0cfbcec5dc4a4bb86d0b69ed56", "status": "affected", "versionType": "git" }, { "version": "420594296838fdc9a674470d710cda7d1487f9f4", "lessThan": "514ca14ed5444b911de59ed3381dfd195d99fe4b", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/powerpc/kernel/smp.c", "include/linux/compiler_attributes.h", "init/main.c" ], "versions": [ { "version": "2.6.30", "status": "affected" }, { "version": "0", "lessThan": "2.6.30", "status": "unaffected", "versionType": "semver" }, { "version": "6.4.4", "lessThanOrEqual": "6.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.5", "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": "2.6.30", "versionEndExcluding": "6.4.4" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.30", "versionEndExcluding": "6.5" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/25e73018b4093e0cfbcec5dc4a4bb86d0b69ed56" }, { "url": "https://git.kernel.org/stable/c/514ca14ed5444b911de59ed3381dfd195d99fe4b" } ], "title": "start_kernel: Add __no_stack_protector function attribute", "x_generator": { "engine": "bippy-1.2.0" } } } }