{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-64082","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-07-19T07:54:57.031Z","datePublished":"2026-07-19T15:39:54.074Z","dateUpdated":"2026-08-05T12:39:01.862Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-05T12:39:01.862Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nriscv: Fix register corruption from uninitialized cregs on error\n\ncompat_riscv_gpr_set() calls cregs_to_regs() unconditionally, even when\nuser_regset_copyin() fails. Since cregs is an uninitialized stack\nvariable, a copyin failure causes uninitialized stack data to be written\ninto the target task's pt_regs, corrupting its register state and\npotentially leaking kernel stack contents.\n\ncompat_restore_sigcontext() has the same issue: it calls cregs_to_regs()\neven when __copy_from_user() fails, leading to the same corruption of\nthe signal-returning task's register state on error.\n\nOnly call cregs_to_regs() when the user copy succeeds."}],"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 bug is only reachable through local kernel interfaces—compat_rt_sigreturn and ptrace(PTRACE_SETREGSET)—with no network, adjacent-radio, or physical-device code path involved.\nAC:L - An attacker can reliably force the user copy to fail by racing munmap/mprotect against sigreturn or ptrace SETREGSET after access_ok, controlling both sides of the TOCTOU window.\nPR:L - The lowest-privilege path is compat_rt_sigreturn, callable by any unprivileged 32-bit compat process on a CONFIG_COMPAT RISC-V system without capabilities or root.\nUI:N - Exploitation requires no victim interaction; a local attacker corrupts their own task’s registers via rt_sigreturn or a tracee they already control as parent/tracer.\nS:U - Impact is confined to kernel register-state corruption and information disclosure within the same OS security boundary, not a VM escape or cross-authority sandbox breakout.\nC:H - On copy failure, uninitialized kernel stack data (up to the full compat_user_regs_struct) is written into pt_regs, leaking kernel memory contents into user-observable registers.\nI:H - The corruption overwrites all general-purpose registers in pt_regs—including program counter, stack pointer, and return address—constituting memory corruption exploitable for control-flow hijacking.\nA:H - Corrupted pt_regs reliably cause faults, SIGSEGV delivery, or erratic kernel/user execution, and the condition is repeatable for 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":["arch/riscv/kernel/compat_signal.c","arch/riscv/kernel/ptrace.c"],"versions":[{"version":"7383ee05314be58f8f9f018ee0ac53bef3808aea","lessThan":"9e020156833f1ad0d425a1e3d85b65639f1c1c50","status":"affected","versionType":"git"},{"version":"7383ee05314be58f8f9f018ee0ac53bef3808aea","lessThan":"6ebcbb53fc9bc30843054ed99fd60b8e542628f4","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/riscv/kernel/compat_signal.c","arch/riscv/kernel/ptrace.c"],"versions":[{"version":"5.19","status":"affected"},{"version":"0","lessThan":"5.19","status":"unaffected","versionType":"semver"},{"version":"7.0.11","lessThanOrEqual":"7.0.*","status":"unaffected","versionType":"semver"},{"version":"7.1","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":"5.19","versionEndExcluding":"7.0.11"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.19","versionEndExcluding":"7.1"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/9e020156833f1ad0d425a1e3d85b65639f1c1c50"},{"url":"https://git.kernel.org/stable/c/6ebcbb53fc9bc30843054ed99fd60b8e542628f4"}],"title":"riscv: Fix register corruption from uninitialized cregs on error","x_generator":{"engine":"bippy-1.2.0"}}}}