{"resultsPerPage":1,"startIndex":0,"totalResults":1,"format":"NVD_CVE","version":"2.0","timestamp":"2026-05-12T18:27:13.070","vulnerabilities":[{"cve":{"id":"CVE-2025-21881","sourceIdentifier":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","published":"2025-03-27T15:15:56.000","lastModified":"2025-11-03T20:17:25.100","vulnStatus":"Modified","cveTags":[],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nuprobes: Reject the shared zeropage in uprobe_write_opcode()\n\nWe triggered the following crash in syzkaller tests:\n\n  BUG: Bad page state in process syz.7.38  pfn:1eff3\n  page: refcount:0 mapcount:0 mapping:0000000000000000 index:0x0 pfn:0x1eff3\n  flags: 0x3fffff00004004(referenced|reserved|node=0|zone=1|lastcpupid=0x1fffff)\n  raw: 003fffff00004004 ffffe6c6c07bfcc8 ffffe6c6c07bfcc8 0000000000000000\n  raw: 0000000000000000 0000000000000000 00000000fffffffe 0000000000000000\n  page dumped because: PAGE_FLAGS_CHECK_AT_FREE flag(s) set\n  Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 04/01/2014\n  Call Trace:\n   <TASK>\n   dump_stack_lvl+0x32/0x50\n   bad_page+0x69/0xf0\n   free_unref_page_prepare+0x401/0x500\n   free_unref_page+0x6d/0x1b0\n   uprobe_write_opcode+0x460/0x8e0\n   install_breakpoint.part.0+0x51/0x80\n   register_for_each_vma+0x1d9/0x2b0\n   __uprobe_register+0x245/0x300\n   bpf_uprobe_multi_link_attach+0x29b/0x4f0\n   link_create+0x1e2/0x280\n   __sys_bpf+0x75f/0xac0\n   __x64_sys_bpf+0x1a/0x30\n   do_syscall_64+0x56/0x100\n   entry_SYSCALL_64_after_hwframe+0x78/0xe2\n\n   BUG: Bad rss-counter state mm:00000000452453e0 type:MM_FILEPAGES val:-1\n\nThe following syzkaller test case can be used to reproduce:\n\n  r2 = creat(&(0x7f0000000000)='./file0\\x00', 0x8)\n  write$nbd(r2, &(0x7f0000000580)=ANY=[], 0x10)\n  r4 = openat(0xffffffffffffff9c, &(0x7f0000000040)='./file0\\x00', 0x42, 0x0)\n  mmap$IORING_OFF_SQ_RING(&(0x7f0000ffd000/0x3000)=nil, 0x3000, 0x0, 0x12, r4, 0x0)\n  r5 = userfaultfd(0x80801)\n  ioctl$UFFDIO_API(r5, 0xc018aa3f, &(0x7f0000000040)={0xaa, 0x20})\n  r6 = userfaultfd(0x80801)\n  ioctl$UFFDIO_API(r6, 0xc018aa3f, &(0x7f0000000140))\n  ioctl$UFFDIO_REGISTER(r6, 0xc020aa00, &(0x7f0000000100)={{&(0x7f0000ffc000/0x4000)=nil, 0x4000}, 0x2})\n  ioctl$UFFDIO_ZEROPAGE(r5, 0xc020aa04, &(0x7f0000000000)={{&(0x7f0000ffd000/0x1000)=nil, 0x1000}})\n  r7 = bpf$PROG_LOAD(0x5, &(0x7f0000000140)={0x2, 0x3, &(0x7f0000000200)=ANY=[@ANYBLOB=\"1800000000120000000000000000000095\"], &(0x7f0000000000)='GPL\\x00', 0x7, 0x0, 0x0, 0x0, 0x0, '\\x00', 0x0, @fallback=0x30, 0xffffffffffffffff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x0, @void, @value}, 0x94)\n  bpf$BPF_LINK_CREATE_XDP(0x1c, &(0x7f0000000040)={r7, 0x0, 0x30, 0x1e, @val=@uprobe_multi={&(0x7f0000000080)='./file0\\x00', &(0x7f0000000100)=[0x2], 0x0, 0x0, 0x1}}, 0x40)\n\nThe cause is that zero pfn is set to the PTE without increasing the RSS\ncount in mfill_atomic_pte_zeropage() and the refcount of zero folio does\nnot increase accordingly. Then, the operation on the same pfn is performed\nin uprobe_write_opcode()->__replace_page() to unconditional decrease the\nRSS count and old_folio's refcount.\n\nTherefore, two bugs are introduced:\n\n 1. The RSS count is incorrect, when process exit, the check_mm() report\n    error \"Bad rss-count\".\n\n 2. The reserved folio (zero folio) is freed when folio->refcount is zero,\n    then free_pages_prepare->free_page_is_bad() report error\n    \"Bad page state\".\n\nThere is more, the following warning could also theoretically be triggered:\n\n  __replace_page()\n    -> ...\n      -> folio_remove_rmap_pte()\n        -> VM_WARN_ON_FOLIO(is_zero_folio(folio), folio)\n\nConsidering that uprobe hit on the zero folio is a very rare case, just\nreject zero old folio immediately after get_user_page_vma_remote().\n\n[ mingo: Cleaned up the changelog ]"},{"lang":"es","value":"En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: uprobes: Rechazar la página cero compartida en uprobe_write_opcode() Activamos el siguiente fallo en las pruebas de syzkaller: ERROR: Estado de página incorrecto en el proceso syz.7.38 pfn:1eff3 page: refcount:0 mapcount:0 mapping:000000000000000 index:0x0 pfn:0x1eff3 flags: 0x3fffff00004004(referenced|reserved|node=0|zone=1|lastcpupid=0x1fffff) raw: 003fffff00004004 ffffe6c6c07bfcc8 ffffe6c6c07bfcc8 000000000000000 raw: 000000000000000 0000000000000000 00000000ffffffffe 0000000000000000 página volcada porque: PAGE_FLAGS_CHECK_AT_FREE indicador(es) establecido(s) Nombre del hardware: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.13.0-1ubuntu1.1 01/04/2014 Seguimiento de llamadas:  dump_stack_lvl+0x32/0x50 bad_page+0x69/0xf0 free_unref_page_prepare+0x401/0x500 free_unref_page+0x6d/0x1b0 uprobe_write_opcode+0x460/0x8e0 install_breakpoint.part.0+0x51/0x80 register_for_each_vma+0x1d9/0x2b0 __uprobe_register+0x245/0x300 bpf_uprobe_multi_link_attach+0x29b/0x4f0 link_create+0x1e2/0x280 __sys_bpf+0x75f/0xac0 __x64_sys_bpf+0x1a/0x30 do_syscall_64+0x56/0x100 entry_SYSCALL_64_after_hwframe+0x78/0xe2 BUG: Bad rss-counter state mm:00000000452453e0 type:MM_FILEPAGES val:-1 The following syzkaller test case can be used to reproduce: r2 = creat(&amp;(0x7f0000000000)='./file0\\x00', 0x8) write$nbd(r2, &amp;(0x7f0000000580)=ANY=[], 0x10) r4 = openat(0xffffffffffffff9c, &amp;(0x7f0000000040)='./file0\\x00', 0x42, 0x0) mmap$IORING_OFF_SQ_RING(&amp;(0x7f0000ffd000/0x3000)=nil, 0x3000, 0x0, 0x12, r4, 0x0) r5 = userfaultfd(0x80801) ioctl$UFFDIO_API(r5, 0xc018aa3f, &amp;(0x7f0000000040)={0xaa, 0x20}) r6 = userfaultfd(0x80801) ioctl$UFFDIO_API(r6, 0xc018aa3f, &amp;(0x7f0000000140)) ioctl$UFFDIO_REGISTER(r6, 0xc020aa00, &amp;(0x7f0000000100)={{&amp;(0x7f0000ffc000/0x4000)=nil, 0x4000}, 0x2}) ioctl$UFFDIO_ZEROPAGE(r5, 0xc020aa04, &amp;(0x7f0000000000)={{&amp;(0x7f0000ffd000/0x1000)=nil, 0x1000}}) r7 = bpf$PROG_LOAD(0x5, &amp;(0x7f0000000140)={0x2, 0x3, &amp;(0x7f0000000200)=ANY=[@ANYBLOB=\"1800000000120000000000000000000095\"], &amp;(0x7f0000000000)='GPL\\x00', 0x7, 0x0, 0x0, 0x0, 0x0, '\\x00', 0x0, @fallback=0x30, 0xffffffffffffffff, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x0, 0x10, 0x0, @void, @value}, 0x94) bpf$BPF_LINK_CREATE_XDP(0x1c, &amp;(0x7f0000000040)={r7, 0x0, 0x30, 0x1e, @val=@uprobe_multi={&amp;(0x7f0000000080)='./file0\\x00', &amp;(0x7f0000000100)=[0x2], 0x0, 0x0, 0x1}}, 0x40) La causa es que cero El pfn se establece en el PTE sin aumentar el recuento RSS en mfill_atomic_pte_zeropage() y el recuento de referencias del folio cero no aumenta en consecuencia. Luego, se realiza la misma operación en el pfn en uprobe_write_opcode()-&gt;__replace_page() para disminuir incondicionalmente el recuento RSS y el recuento de referencias de old_folio. Por lo tanto, se introducen dos errores: 1. El recuento RSS es incorrecto; al finalizar el proceso, check_mm() informa el error \"Bad RSS-count\" (recuento RSS incorrecto). 2. El folio reservado (folio cero) se libera cuando folio-&gt;refcount es cero; entonces, free_pages_prepare-&gt;free_page_is_bad() informa el error \"Bad page state\" (estado de página incorrecto). Hay más, la siguiente advertencia también podría activarse teóricamente: __replace_page() -&gt; ... -&gt; folio_remove_rmap_pte() -&gt; VM_WARN_ON_FOLIO(is_zero_folio(folio), folio) Teniendo en cuenta que el impacto de uprobe en el folio cero es un caso muy raro, simplemente rechace el folio antiguo cero inmediatamente después de get_user_page_vma_remote(). [ mingo: Se limpió el registro de cambios ]"}],"metrics":{"cvssMetricV31":[{"source":"nvd@nist.gov","type":"Primary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","baseScore":5.5,"baseSeverity":"MEDIUM","attackVector":"LOCAL","attackComplexity":"LOW","privilegesRequired":"LOW","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":1.8,"impactScore":3.6}]},"weaknesses":[{"source":"nvd@nist.gov","type":"Primary","description":[{"lang":"en","value":"NVD-CWE-noinfo"}]}],"configurations":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"3.5","versionEndExcluding":"6.1.130","matchCriteriaId":"3493C8F1-7D86-400D-B13B-BE0A4FADAE02"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.2","versionEndExcluding":"6.6.81","matchCriteriaId":"8C92C9CD-2ADE-412E-A7FF-DC9E0630B25D"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.7","versionEndExcluding":"6.12.18","matchCriteriaId":"3D5C8D9A-4013-4C1A-810F-AA540BB5737C"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.13","versionEndExcluding":"6.13.6","matchCriteriaId":"64F12D9B-71C2-4CD7-A288-0D5EF1709620"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.14:rc1:*:*:*:*:*:*","matchCriteriaId":"186716B6-2B66-4BD0-852E-D48E71C0C85F"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.14:rc2:*:*:*:*:*:*","matchCriteriaId":"0D3E781C-403A-498F-9DA9-ECEE50F41E75"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.14:rc3:*:*:*:*:*:*","matchCriteriaId":"66619FB8-0AAF-4166-B2CF-67B24143261D"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:6.14:rc4:*:*:*:*:*:*","matchCriteriaId":"D3D6550E-6679-4560-902D-AF52DCFE905B"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/0b6f19714588cf2366b0364234f97ba963688f63","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/13cca2b73e2b0ec3ea6d6615d615395621d22752","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/54011fc94422f094eaf47555284de70a4bc32bb9","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/bddf10d26e6e5114e7415a0e442ec6f51a559468","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://git.kernel.org/stable/c/c4cb2bfa99513311886c1eb5c1c2ac26f3338a6e","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":["Patch"]},{"url":"https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html","source":"af854a3a-2127-422b-91ae-364da2661108"}]}}]}