{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2024-26706", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-02-19T14:20:24.158Z", "datePublished": "2024-04-03T14:55:09.529Z", "dateUpdated": "2026-08-05T11:26:48.578Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-08-05T11:26:48.578Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nparisc: Fix random data corruption from exception handler\n\nThe current exception handler implementation, which assists when accessing\nuser space memory, may exhibit random data corruption if the compiler decides\nto use a different register than the specified register %r29 (defined in\nASM_EXCEPTIONTABLE_REG) for the error code. If the compiler choose another\nregister, the fault handler will nevertheless store -EFAULT into %r29 and thus\ntrash whatever this register is used for.\nLooking at the assembly I found that this happens sometimes in emulate_ldd().\n\nTo solve the issue, the easiest solution would be if it somehow is\npossible to tell the fault handler which register is used to hold the error\ncode. Using %0 or %1 in the inline assembly is not posssible as it will show\nup as e.g. %r29 (with the \"%r\" prefix), which the GNU assembler can not\nconvert to an integer.\n\nThis patch takes another, better and more flexible approach:\nWe extend the __ex_table (which is out of the execution path) by one 32-word.\nIn this word we tell the compiler to insert the assembler instruction\n\"or %r0,%r0,%reg\", where %reg references the register which the compiler\nchoosed for the error return code.\nIn case of an access failure, the fault handler finds the __ex_table entry and\ncan examine the opcode. The used register is encoded in the lowest 5 bits, and\nthe fault handler can then store -EFAULT into this register.\n\nSince we extend the __ex_table to 3 words we can't use the BUILDTIME_TABLE_SORT\nconfig option any longer." } ], "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 - Triggering requires executing an unaligned load/store instruction or issuing a syscall with an invalid user pointer on the affected PA-RISC machine, so the attacker must be able to run code locally. There is no network-reachable path into `handle_unaligned()`/`fixup_exception()`.\nAC:L - The attacker deterministically controls the trigger — mmap a region, unmap the adjacent page, and execute an unaligned access straddling the boundary (or pass a PROT_NONE pointer to any get_user()/put_user() syscall) — and can repeat it at will with no race to win. The only build-dependent factor is which register GCC allocated, a static property of the deployed binary that the attacker can inspect (parisc has no KASLR) and that was confirmed to occur in practice in `emulate_ldd()`.\nPR:L - Any unprivileged local user can execute an unaligned instruction or call a syscall with a bad pointer; no capabilities, namespaces, or special file access are needed. Unaligned emulation is enabled by default (`unaligned_enabled = 1`).\nUI:N - The attacking process triggers the fault entirely on its own by executing the unaligned instruction or making the syscall. No victim action or cooperation is required.\nS:U - The corruption is confined to kernel registers and kernel memory within the same security authority; there is no hypervisor, IOMMU, or sandbox boundary crossed.\nC:H - The fault handler clobbers whatever live kernel value the compiler placed in %r29 — a length, index, or pointer at an attacker-chosen call site — which can be steered into out-of-bounds kernel reads whose results are returned to userspace, and failed get_user()/copy paths are reported as successful so the kernel acts on data it never validly read. Per the guidance, memory corruption leverageable for information disclosure scores High.\nI:H - This is arbitrary kernel data corruption: in `emulate_ldd()` a clobbered `toreg` turns `regs->gr[toreg] = val` into an out-of-bounds write past `pt_regs` on the kernel stack with attacker-influenced data, and failed `put_user()`/`cacheflush()` operations are silently reported as having succeeded. Kernel-stack out-of-bounds writes are a control-flow-hijack primitive.\nA:H - Overwriting a live kernel register with -EFAULT (0xfffffff2) turns pointers and counters into invalid values, producing immediate oops/panic when dereferenced, and the condition is trivially and repeatedly reproducible by an unprivileged user." } ] } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/parisc/Kconfig", "arch/parisc/include/asm/assembly.h", "arch/parisc/include/asm/extable.h", "arch/parisc/include/asm/special_insns.h", "arch/parisc/include/asm/uaccess.h", "arch/parisc/kernel/cache.c", "arch/parisc/kernel/unaligned.c", "arch/parisc/mm/fault.c" ], "versions": [ { "version": "d19f5e41b344a057bb2450024a807476f30978d2", "lessThan": "23027309b099ffc4efca5477009a11dccbdae592", "status": "affected", "versionType": "git" }, { "version": "d19f5e41b344a057bb2450024a807476f30978d2", "lessThan": "fa69a8063f8b27f3c7434a0d4f464a76a62f24d2", "status": "affected", "versionType": "git" }, { "version": "d19f5e41b344a057bb2450024a807476f30978d2", "lessThan": "ce31d79aa1f13a2345791f84935281a2c194e003", "status": "affected", "versionType": "git" }, { "version": "d19f5e41b344a057bb2450024a807476f30978d2", "lessThan": "8b1d72395635af45410b66cc4c4ab37a12c4a831", "status": "affected", "versionType": "git" }, { "version": "09b931fcb87c8aad178475a7db1d4bfc939f7faa", "status": "affected", "versionType": "git" }, { "version": "37e6234297379e0db25e39c2ca99776fea70026c", "status": "affected", "versionType": "git" }, { "version": "4.9.21", "lessThan": "4.10", "status": "affected", "versionType": "semver" }, { "version": "4.10.9", "lessThan": "4.11", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "arch/parisc/Kconfig", "arch/parisc/include/asm/assembly.h", "arch/parisc/include/asm/extable.h", "arch/parisc/include/asm/special_insns.h", "arch/parisc/include/asm/uaccess.h", "arch/parisc/kernel/cache.c", "arch/parisc/kernel/unaligned.c", "arch/parisc/mm/fault.c" ], "versions": [ { "version": "4.11", "status": "affected" }, { "version": "0", "lessThan": "4.11", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.79", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.18", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.7.6", "lessThanOrEqual": "6.7.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.8", "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": "4.11", "versionEndExcluding": "6.1.79" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.6.18" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.7.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.11", "versionEndExcluding": "6.8" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.9.21" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "4.10.9" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/23027309b099ffc4efca5477009a11dccbdae592" }, { "url": "https://git.kernel.org/stable/c/fa69a8063f8b27f3c7434a0d4f464a76a62f24d2" }, { "url": "https://git.kernel.org/stable/c/ce31d79aa1f13a2345791f84935281a2c194e003" }, { "url": "https://git.kernel.org/stable/c/8b1d72395635af45410b66cc4c4ab37a12c4a831" } ], "title": "parisc: Fix random data corruption from exception handler", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "other": { "type": "ssvc", "content": { "timestamp": "2024-06-17T19:29:32.394995Z", "id": "CVE-2024-26706", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-06-17T19:29:43.758Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-02T00:14:12.642Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/23027309b099ffc4efca5477009a11dccbdae592", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/fa69a8063f8b27f3c7434a0d4f464a76a62f24d2", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/ce31d79aa1f13a2345791f84935281a2c194e003", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/8b1d72395635af45410b66cc4c4ab37a12c4a831", "tags": [ "x_transferred" ] } ] } ] } }