{"id":"CVE-2025-68198","state":"PUBLISHED","title":"crash: fix crashkernel resource shrink","description":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrash: fix crashkernel resource shrink\n\nWhen crashkernel is configured with a high reservation, shrinking its\nvalue below the low crashkernel reservation causes two issues:\n\n1. Invalid crashkernel resource objects\n2. Kernel crash if crashkernel shrinking is done twice\n\nFor example, with crashkernel=200M,high, the kernel reserves 200MB of high\nmemory and some default low memory (say 256MB).  The reservation appears\nas:\n\ncat /proc/iomem | grep -i crash\naf000000-beffffff : Crash kernel\n433000000-43f7fffff : Crash kernel\n\nIf crashkernel is then shrunk to 50MB (echo 52428800 >\n/sys/kernel/kexec_crash_size), /proc/iomem still shows 256MB reserved:\naf000000-beffffff : Crash kernel\n\nInstead, it should show 50MB:\naf000000-b21fffff : Crash kernel\n\nFurther shrinking crashkernel to 40MB causes a kernel crash with the\nfollowing trace (x86):\n\nBUG: kernel NULL pointer dereference, address: 0000000000000038\nPGD 0 P4D 0\nOops: 0000 [#1] PREEMPT SMP NOPTI\n<snip...>\nCall Trace: <TASK>\n? __die_body.cold+0x19/0x27\n? page_fault_oops+0x15a/0x2f0\n? search_module_extables+0x19/0x60\n? search_bpf_extables+0x5f/0x80\n? exc_page_fault+0x7e/0x180\n? asm_exc_page_fault+0x26/0x30\n? __release_resource+0xd/0xb0\nrelease_resource+0x26/0x40\n__crash_shrink_memory+0xe5/0x110\ncrash_shrink_memory+0x12a/0x190\nkexec_crash_size_store+0x41/0x80\nkernfs_fop_write_iter+0x141/0x1f0\nvfs_write+0x294/0x460\nksys_write+0x6d/0xf0\n<snip...>\n\nThis happens because __crash_shrink_memory()/kernel/crash_core.c\nincorrectly updates the crashk_res resource object even when\ncrashk_low_res should be updated.\n\nFix this by ensuring the correct crashkernel resource object is updated\nwhen shrinking crashkernel memory.","publishedAt":"2025-12-16T13:48:26.998Z","updatedAt":"2026-05-11T21:48:33.671Z","severity":null,"assigner":"Linux","products":["Linux Linux"],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"f01f9c348d76d40bf104a94449e3ce4057fdefee","versionType":"git"},{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"f89c5e7077f63e45e8ba5a77b7cf0803130367e6","versionType":"git"},{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"a2bd247f8c6c5ac3f0ba823a2fffd77bb9cdf618","versionType":"git"},{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"00fbff75c5acb4755f06f08bd1071879c63940c5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/crash_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"6.6.118","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.59","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.9","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/crash_core.c"]}],"references":["https://git.kernel.org/stable/c/f01f9c348d76d40bf104a94449e3ce4057fdefee","https://git.kernel.org/stable/c/f89c5e7077f63e45e8ba5a77b7cf0803130367e6","https://git.kernel.org/stable/c/a2bd247f8c6c5ac3f0ba823a2fffd77bb9cdf618","https://git.kernel.org/stable/c/00fbff75c5acb4755f06f08bd1071879c63940c5"],"weaknesses":[],"ingestedAt":"2026-10-29T20:09:56.034Z","source":{"repository":"CVEProject/cvelistV5","path":"cves/2025/68xxx/CVE-2025-68198.json","commit":"556c9d3a8cd17e218bb8e452ba7cd619a384ff47"},"raw":{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2025-68198","state":"PUBLISHED","datePublished":"2025-12-16T13:48:26.998Z","dateUpdated":"2026-05-11T21:48:33.671Z","assignerShortName":"Linux","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateReserved":"2025-12-16T13:41:40.254Z"},"containers":{"cna":{"title":"crash: fix crashkernel resource shrink","descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\ncrash: fix crashkernel resource shrink\n\nWhen crashkernel is configured with a high reservation, shrinking its\nvalue below the low crashkernel reservation causes two issues:\n\n1. Invalid crashkernel resource objects\n2. Kernel crash if crashkernel shrinking is done twice\n\nFor example, with crashkernel=200M,high, the kernel reserves 200MB of high\nmemory and some default low memory (say 256MB).  The reservation appears\nas:\n\ncat /proc/iomem | grep -i crash\naf000000-beffffff : Crash kernel\n433000000-43f7fffff : Crash kernel\n\nIf crashkernel is then shrunk to 50MB (echo 52428800 >\n/sys/kernel/kexec_crash_size), /proc/iomem still shows 256MB reserved:\naf000000-beffffff : Crash kernel\n\nInstead, it should show 50MB:\naf000000-b21fffff : Crash kernel\n\nFurther shrinking crashkernel to 40MB causes a kernel crash with the\nfollowing trace (x86):\n\nBUG: kernel NULL pointer dereference, address: 0000000000000038\nPGD 0 P4D 0\nOops: 0000 [#1] PREEMPT SMP NOPTI\n<snip...>\nCall Trace: <TASK>\n? __die_body.cold+0x19/0x27\n? page_fault_oops+0x15a/0x2f0\n? search_module_extables+0x19/0x60\n? search_bpf_extables+0x5f/0x80\n? exc_page_fault+0x7e/0x180\n? asm_exc_page_fault+0x26/0x30\n? __release_resource+0xd/0xb0\nrelease_resource+0x26/0x40\n__crash_shrink_memory+0xe5/0x110\ncrash_shrink_memory+0x12a/0x190\nkexec_crash_size_store+0x41/0x80\nkernfs_fop_write_iter+0x141/0x1f0\nvfs_write+0x294/0x460\nksys_write+0x6d/0xf0\n<snip...>\n\nThis happens because __crash_shrink_memory()/kernel/crash_core.c\nincorrectly updates the crashk_res resource object even when\ncrashk_low_res should be updated.\n\nFix this by ensuring the correct crashkernel resource object is updated\nwhen shrinking crashkernel memory."}],"affected":[{"vendor":"Linux","product":"Linux","defaultStatus":"unaffected","versions":[{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"f01f9c348d76d40bf104a94449e3ce4057fdefee","versionType":"git"},{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"f89c5e7077f63e45e8ba5a77b7cf0803130367e6","versionType":"git"},{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"a2bd247f8c6c5ac3f0ba823a2fffd77bb9cdf618","versionType":"git"},{"version":"16c6006af4d4e70ecef93977a5314409d931020b","status":"affected","lessThan":"00fbff75c5acb4755f06f08bd1071879c63940c5","versionType":"git"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/crash_core.c"]},{"vendor":"Linux","product":"Linux","defaultStatus":"affected","versions":[{"version":"6.5","status":"affected"},{"version":"0","status":"unaffected","lessThan":"6.5","versionType":"semver"},{"version":"6.6.118","status":"unaffected","lessThanOrEqual":"6.6.*","versionType":"semver"},{"version":"6.12.59","status":"unaffected","lessThanOrEqual":"6.12.*","versionType":"semver"},{"version":"6.17.9","status":"unaffected","lessThanOrEqual":"6.17.*","versionType":"semver"},{"version":"6.18","status":"unaffected","lessThanOrEqual":"*","versionType":"original_commit_for_fix"}],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["kernel/crash_core.c"]}],"references":[{"url":"https://git.kernel.org/stable/c/f01f9c348d76d40bf104a94449e3ce4057fdefee"},{"url":"https://git.kernel.org/stable/c/f89c5e7077f63e45e8ba5a77b7cf0803130367e6"},{"url":"https://git.kernel.org/stable/c/a2bd247f8c6c5ac3f0ba823a2fffd77bb9cdf618"},{"url":"https://git.kernel.org/stable/c/00fbff75c5acb4755f06f08bd1071879c63940c5"}],"providerMetadata":{"shortName":"Linux","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","dateUpdated":"2026-05-11T21:48:33.671Z"},"cpeApplicability":[{"nodes":[{"operator":"OR","negate":false,"cpeMatch":[{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.6.118"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.12.59"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.17.9"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"6.5","versionEndExcluding":"6.18"}]}]}],"x_generator":{"engine":"bippy-1.2.0"}}}}}