{"id":"CVE-2025-38033","summary":"x86/Kconfig: make CFI_AUTO_DEFAULT depend on !RUST or Rust \u003e= 1.88","details":"In the Linux kernel, the following vulnerability has been resolved:\n\nx86/Kconfig: make CFI_AUTO_DEFAULT depend on !RUST or Rust \u003e= 1.88\n\nCalling core::fmt::write() from rust code while FineIBT is enabled\nresults in a kernel panic:\n\n[ 4614.199779] kernel BUG at arch/x86/kernel/cet.c:132!\n[ 4614.205343] Oops: invalid opcode: 0000 [#1] PREEMPT SMP NOPTI\n[ 4614.211781] CPU: 2 UID: 0 PID: 6057 Comm: dmabuf_dump Tainted: G     U     O       6.12.17-android16-0-g6ab38c534a43 #1 9da040f27673ec3945e23b998a0f8bd64c846599\n[ 4614.227832] Tainted: [U]=USER, [O]=OOT_MODULE\n[ 4614.241247] RIP: 0010:do_kernel_cp_fault+0xea/0xf0\n...\n[ 4614.398144] RIP: 0010:_RNvXs5_NtNtNtCs3o2tGsuHyou_4core3fmt3num3impyNtB9_7Display3fmt+0x0/0x20\n[ 4614.407792] Code: 48 f7 df 48 0f 48 f9 48 89 f2 89 c6 5d e9 18 fd ff ff 0f 1f 84 00 00 00 00 00 f3 0f 1e fa 41 81 ea 14 61 af 2c 74 03 0f 0b 90 \u003c66\u003e 0f 1f 00 55 48 89 e5 48 89 f2 48 8b 3f be 01 00 00 00 5d e9 e7\n[ 4614.428775] RSP: 0018:ffffb95acfa4ba68 EFLAGS: 00010246\n[ 4614.434609] RAX: 0000000000000000 RBX: 0000000000000010 RCX: 0000000000000000\n[ 4614.442587] RDX: 0000000000000007 RSI: ffffb95acfa4ba70 RDI: ffffb95acfa4bc88\n[ 4614.450557] RBP: ffffb95acfa4bae0 R08: ffff0a00ffffff05 R09: 0000000000000070\n[ 4614.458527] R10: 0000000000000000 R11: ffffffffab67eaf0 R12: ffffb95acfa4bcc8\n[ 4614.466493] R13: ffffffffac5d50f0 R14: 0000000000000000 R15: 0000000000000000\n[ 4614.474473]  ? __cfi__RNvXs5_NtNtNtCs3o2tGsuHyou_4core3fmt3num3impyNtB9_7Display3fmt+0x10/0x10\n[ 4614.484118]  ? _RNvNtCs3o2tGsuHyou_4core3fmt5write+0x1d2/0x250\n\nThis happens because core::fmt::write() calls\ncore::fmt::rt::Argument::fmt(), which currently has CFI disabled:\n\nlibrary/core/src/fmt/rt.rs:\n171     // FIXME: Transmuting formatter in new and indirectly branching to/calling\n172     // it here is an explicit CFI violation.\n173     #[allow(inline_no_sanitize)]\n174     #[no_sanitize(cfi, kcfi)]\n175     #[inline]\n176     pub(super) unsafe fn fmt(&self, f: &mut Formatter\u003c'_\u003e) -\u003e Result {\n\nThis causes a Control Protection exception, because FineIBT has sealed\noff the original function's endbr64.\n\nThis makes rust currently incompatible with FineIBT. Add a Kconfig\ndependency that prevents FineIBT from getting turned on by default\nif rust is enabled.\n\n[ Rust 1.88.0 (scheduled for 2025-06-26) should have this fixed [1],\n  and thus we relaxed the condition with Rust \u003e= 1.88.\n\n  When `objtool` lands checking for this with e.g. [2], the plan is\n  to ideally run that in upstream Rust's CI to prevent regressions\n  early [3], since we do not control `core`'s source code.\n\n  Alice tested the Rust PR backported to an older compiler.\n\n  Peter would like that Rust provides a stable `core` which can be\n  pulled into the kernel: \"Relying on that much out of tree code is\n  'unfortunate'\".\n\n    - Miguel ]\n\n[ Reduced splat. - Miguel ]","modified":"2026-04-02T12:47:45.038653Z","published":"2025-06-18T09:33:20.195Z","database_specific":{"cna_assigner":"Linux","osv_generated_from":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38033.json"},"references":[{"type":"WEB","url":"https://git.kernel.org/stable/c/5595c31c370957aabe739ac3996aedba8267603f"},{"type":"WEB","url":"https://git.kernel.org/stable/c/5a8d073d87da4ad1496b35adaee5719e94665d81"},{"type":"WEB","url":"https://git.kernel.org/stable/c/6b9956d09382bcbd5fd260c4b60ec48680a4cffb"},{"type":"ADVISORY","url":"https://github.com/CVEProject/cvelistV5/tree/main/cves/2025/38xxx/CVE-2025-38033.json"},{"type":"ADVISORY","url":"https://nvd.nist.gov/vuln/detail/CVE-2025-38033"},{"type":"PACKAGE","url":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git"}],"affected":[{"ranges":[{"type":"GIT","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","events":[{"introduced":"d6f635bcaca8d38dfa47ee20658705f9eff156b5"},{"fixed":"5a8d073d87da4ad1496b35adaee5719e94665d81"},{"fixed":"6b9956d09382bcbd5fd260c4b60ec48680a4cffb"},{"fixed":"5595c31c370957aabe739ac3996aedba8267603f"}]}],"database_specific":{"source":"https://storage.googleapis.com/cve-osv-conversion/osv-output/CVE-2025-38033.json"}}],"schema_version":"1.7.5"}