{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2026-80631","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2026-08-26T14:34:25.776Z","datePublished":"2026-08-28T06:48:47.166Z","dateUpdated":"2026-08-29T06:21:31.506Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2026-08-29T06:21:31.506Z"},"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":{"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"},"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."}]}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/btrfs/lzo.c"],"versions":[{"version":"a6e66e6f8c1b685e11b778bef614480a9c1a5278","lessThan":"1641d058adfbd50cf95d54581ed5d142ee82c07f","status":"affected","versionType":"git"},{"version":"a6e66e6f8c1b685e11b778bef614480a9c1a5278","lessThan":"b0d27d43791b7a3057c3c4aedf9b4aa033d37c46","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["fs/btrfs/lzo.c"],"versions":[{"version":"5.15","status":"affected"},{"version":"0","lessThan":"5.15","status":"unaffected","versionType":"semver"},{"version":"7.1.5","lessThanOrEqual":"7.1.*","status":"unaffected","versionType":"semver"},{"version":"7.2","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":"5.15","versionEndExcluding":"7.1.5"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"5.15","versionEndExcluding":"7.2"}]}]}],"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"}}}}