{"api_version":"1","generated_at":"2026-08-29T12:13:31+00:00","cve":"CVE-2026-80631","urls":{"html":"https://cve.report/CVE-2026-80631","api":"https://cve.report/api/cve/CVE-2026-80631.json","docs":"https://cve.report/api","cve_org":"https://www.cve.org/CVERecord?id=CVE-2026-80631","nvd":"https://nvd.nist.gov/vuln/detail/CVE-2026-80631"},"summary":{"title":"btrfs: lzo: reject compressed segment that overflows the compressed input","description":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: lzo: reject compressed segment that overflows the compressed input\n\nlzo_decompress_bio() validates each on-disk segment length seg_len only\nagainst the workspace cbuf size, not against the compressed input size\n(compressed_len, the total folio bytes of the bio).  A crafted extent can\ncarry a segment whose seg_len passes the cbuf check but runs past the end\nof the bio, so copy_compressed_segment() walks off the last folio:\nget_current_folio() then returns the NULL folio from bio_next_folio(), and\nwith CONFIG_BTRFS_ASSERT disabled (default) folio_size(NULL) faults.\n\n BUG: KASAN: null-ptr-deref in lzo_decompress_bio (fs/btrfs/lzo.c:383)\n Read of size 8 at addr 0000000000000000 by task kworker/u8:1/29\n Workqueue: btrfs-endio simple_end_io_work\n  kasan_report (mm/kasan/report.c:590)\n  lzo_decompress_bio (fs/btrfs/lzo.c:383)\n  end_bbio_compressed_read (fs/btrfs/compression.c:1065)\n  btrfs_bio_end_io (fs/btrfs/bio.c:135)\n  btrfs_check_read_bio (fs/btrfs/bio.c:180 fs/btrfs/bio.c:285)\n  simple_end_io_work\n  process_one_work\n  worker_thread\n\nReject any segment whose payload would extend beyond compressed_len before\ncopying it, treating it as corruption like the other on-disk validation\nfailures in this function.","state":"PUBLISHED","assigner":"Linux","published_at":"2026-08-28 08:16:48","updated_at":"2026-08-29 07:16:47"},"problem_types":[],"metrics":[{"version":"3.1","source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"}},{"version":"3.1","source":"CNA","type":"DECLARED","score":"7.5","severity":"HIGH","vector":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","data":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"}}],"references":[{"url":"https://git.kernel.org/stable/c/b0d27d43791b7a3057c3c4aedf9b4aa033d37c46","name":"https://git.kernel.org/stable/c/b0d27d43791b7a3057c3c4aedf9b4aa033d37c46","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://git.kernel.org/stable/c/1641d058adfbd50cf95d54581ed5d142ee82c07f","name":"https://git.kernel.org/stable/c/1641d058adfbd50cf95d54581ed5d142ee82c07f","refsource":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","tags":[],"title":"","mime":"","httpstatus":"","archivestatus":"0"},{"url":"https://www.cve.org/CVERecord?id=CVE-2026-80631","name":"CVE Program record","refsource":"CVE.ORG","tags":["canonical"]},{"url":"https://nvd.nist.gov/vuln/detail/CVE-2026-80631","name":"NVD vulnerability detail","refsource":"NVD","tags":["canonical","analysis"]}],"affected":[{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a6e66e6f8c1b685e11b778bef614480a9c1a5278 1641d058adfbd50cf95d54581ed5d142ee82c07f git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected a6e66e6f8c1b685e11b778bef614480a9c1a5278 b0d27d43791b7a3057c3c4aedf9b4aa033d37c46 git","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"affected 5.15","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 5.15 semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.1.5 7.1.* semver","platforms":[]},{"source":"CNA","vendor":"Linux","product":"Linux","version":"unaffected 7.2 * original_commit_for_fix","platforms":[]}],"timeline":[],"solutions":[],"workarounds":[],"exploits":[],"credits":[],"nvd_cpes":[],"vendor_comments":[],"enrichments":{"kev":null,"epss":{"cve_year":"2026","cve_id":"80631","cve":"CVE-2026-80631","epss":"0.001550000","percentile":"0.049830000","score_date":"2026-08-28","updated_at":"2026-08-29 00:12:17"},"legacy_qids":[]},"source_records":{"cve_program":{"containers":{"cna":{"affected":[{"defaultStatus":"unaffected","product":"Linux","programFiles":["fs/btrfs/lzo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"lessThan":"1641d058adfbd50cf95d54581ed5d142ee82c07f","status":"affected","version":"a6e66e6f8c1b685e11b778bef614480a9c1a5278","versionType":"git"},{"lessThan":"b0d27d43791b7a3057c3c4aedf9b4aa033d37c46","status":"affected","version":"a6e66e6f8c1b685e11b778bef614480a9c1a5278","versionType":"git"}]},{"defaultStatus":"affected","product":"Linux","programFiles":["fs/btrfs/lzo.c"],"repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","vendor":"Linux","versions":[{"status":"affected","version":"5.15"},{"lessThan":"5.15","status":"unaffected","version":"0","versionType":"semver"},{"lessThanOrEqual":"7.1.*","status":"unaffected","version":"7.1.5","versionType":"semver"},{"lessThanOrEqual":"*","status":"unaffected","version":"7.2","versionType":"original_commit_for_fix"}]}],"cpeApplicability":[{"nodes":[{"cpeMatch":[{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.1.5","versionStartIncluding":"5.15","vulnerable":true},{"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionEndExcluding":"7.2","versionStartIncluding":"5.15","vulnerable":true}],"negate":false,"operator":"OR"}]}],"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: lzo: reject compressed segment that overflows the compressed input\n\nlzo_decompress_bio() validates each on-disk segment length seg_len only\nagainst the workspace cbuf size, not against the compressed input size\n(compressed_len, the total folio bytes of the bio).  A crafted extent can\ncarry a segment whose seg_len passes the cbuf check but runs past the end\nof the bio, so copy_compressed_segment() walks off the last folio:\nget_current_folio() then returns the NULL folio from bio_next_folio(), and\nwith CONFIG_BTRFS_ASSERT disabled (default) folio_size(NULL) faults.\n\n BUG: KASAN: null-ptr-deref in lzo_decompress_bio (fs/btrfs/lzo.c:383)\n Read of size 8 at addr 0000000000000000 by task kworker/u8:1/29\n Workqueue: btrfs-endio simple_end_io_work\n  kasan_report (mm/kasan/report.c:590)\n  lzo_decompress_bio (fs/btrfs/lzo.c:383)\n  end_bbio_compressed_read (fs/btrfs/compression.c:1065)\n  btrfs_bio_end_io (fs/btrfs/bio.c:135)\n  btrfs_check_read_bio (fs/btrfs/bio.c:180 fs/btrfs/bio.c:285)\n  simple_end_io_work\n  process_one_work\n  worker_thread\n\nReject any segment whose payload would extend beyond compressed_len before\ncopying it, treating it as corruption like the other on-disk validation\nfailures in this function."}],"metrics":[{"cvssV3_1":{"baseScore":7.5,"baseSeverity":"HIGH","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","version":"3.1"},"scenarios":[{"lang":"en","value":"AV:N - On btrfs-backed NAS/cloud storage exported via nfsd or ksmbd, a remote client's read I/O is served by the server kernel through btrfs_do_readpage→btrfs_submit_compressed_read→lzo_decompress_bio, reaching the vulnerable LZO segment parser without local syscall access on the server.\nAC:L - A crafted on-disk LZO segment header with seg_len that passes the cbuf-size check but exceeds remaining compressed_len deterministically drives copy_compressed_segment past the last bio folio; no race, special memory layout, or rare kernel config is required.\nPR:N - Triggering needs only read access to btrfs content on an already-mounted/exported volume (e.g., NFS/ksmbd read); planting malformed LZO segment metadata is done via offline btrfs image crafting and does not require init-namespace root or a local account on the victim.\nUI:N - Exploitation is the attacker's own read against a btrfs volume that already contains the crafted LZO-compressed extent (backup restore, shared storage, or export); no separate victim mount, click, or plug-in action is needed beyond that read.\nS:U - Impact is a kernel NULL-pointer dereference and oops in the btrfs-endio workqueue on the host parsing attacker-supplied compressed data; this is standard host-kernel failure within one security authority, not VM escape or IOMMU bypass.\nC:N - The demonstrated failure is a null-ptr-deref read at address 0 in folio_size(NULL) when walking past the bio; unlike slab OOB reads in related btrfs LZO bugs, no adjacent kernel memory is disclosed before the fault.\nI:N - The bug faults during folio iteration before completing an out-of-bounds copy or decompression; there is no demonstrated or plausible kernel heap/stack write, control-flow hijack, or other integrity corruption beyond attacker-controlled on-disk bytes already in the bio.\nA:H - The NULL dereference in lzo_decompress_bio runs in btrfs-endio kworker context and produces a KASAN-reported kernel oops/panic; any process read (local or remote via NFS/ksmbd) of the crafted extent can repeatedly crash the host."}]}],"providerMetadata":{"dateUpdated":"2026-08-29T06:21:31.506Z","orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux"},"references":[{"url":"https://git.kernel.org/stable/c/1641d058adfbd50cf95d54581ed5d142ee82c07f"},{"url":"https://git.kernel.org/stable/c/b0d27d43791b7a3057c3c4aedf9b4aa033d37c46"}],"title":"btrfs: lzo: reject compressed segment that overflows the compressed input","x_generator":{"engine":"bippy-1.2.0"}}},"cveMetadata":{"assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","assignerShortName":"Linux","cveId":"CVE-2026-80631","datePublished":"2026-08-28T06:48:47.166Z","dateReserved":"2026-08-26T14:34:25.776Z","dateUpdated":"2026-08-29T06:21:31.506Z","state":"PUBLISHED"},"dataType":"CVE_RECORD","dataVersion":"5.2"},"nvd":{"publishedDate":"2026-08-28 08:16:48","lastModifiedDate":"2026-08-29 07:16:47","problem_types":[],"metrics":{"cvssMetricV31":[{"source":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","type":"Secondary","cvssData":{"version":"3.1","vectorString":"CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H","baseScore":7.5,"baseSeverity":"HIGH","attackVector":"NETWORK","attackComplexity":"LOW","privilegesRequired":"NONE","userInteraction":"NONE","scope":"UNCHANGED","confidentialityImpact":"NONE","integrityImpact":"NONE","availabilityImpact":"HIGH"},"exploitabilityScore":3.9,"impactScore":3.6}]},"configurations":[]},"legacy_mitre":{"record":{"CveYear":"2026","CveId":"80631","Ordinal":"1","Title":"btrfs: lzo: reject compressed segment that overflows the compres","CVE":"CVE-2026-80631","Year":"2026"},"notes":[{"CveYear":"2026","CveId":"80631","Ordinal":"1","NoteData":"In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: lzo: reject compressed segment that overflows the compressed input\n\nlzo_decompress_bio() validates each on-disk segment length seg_len only\nagainst the workspace cbuf size, not against the compressed input size\n(compressed_len, the total folio bytes of the bio).  A crafted extent can\ncarry a segment whose seg_len passes the cbuf check but runs past the end\nof the bio, so copy_compressed_segment() walks off the last folio:\nget_current_folio() then returns the NULL folio from bio_next_folio(), and\nwith CONFIG_BTRFS_ASSERT disabled (default) folio_size(NULL) faults.\n\n BUG: KASAN: null-ptr-deref in lzo_decompress_bio (fs/btrfs/lzo.c:383)\n Read of size 8 at addr 0000000000000000 by task kworker/u8:1/29\n Workqueue: btrfs-endio simple_end_io_work\n  kasan_report (mm/kasan/report.c:590)\n  lzo_decompress_bio (fs/btrfs/lzo.c:383)\n  end_bbio_compressed_read (fs/btrfs/compression.c:1065)\n  btrfs_bio_end_io (fs/btrfs/bio.c:135)\n  btrfs_check_read_bio (fs/btrfs/bio.c:180 fs/btrfs/bio.c:285)\n  simple_end_io_work\n  process_one_work\n  worker_thread\n\nReject any segment whose payload would extend beyond compressed_len before\ncopying it, treating it as corruption like the other on-disk validation\nfailures in this function.","Type":"Description","Title":"btrfs: lzo: reject compressed segment that overflows the compres"}]}}}