{"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"]}]}]}}