CVE-2026-68167 (GCVE-0-2026-68167)

Vulnerability from cvelistv5 – Published: 2026-08-10 11:59 – Updated: 2026-08-17 05:00
VLAI
Title
btrfs: do not try compression for data reloc inodes
Summary
In the Linux kernel, the following vulnerability has been resolved: btrfs: do not try compression for data reloc inodes [BUG] There is a syzbot report that the check inside get_new_location() triggered: BTRFS info (device loop0): found 31 extents, stage: move data extents BTRFS info (device loop0): leaf 8908800 gen 16 total ptrs 28 free space 1676 owner 18446744073709551607 item 0 key (256 INODE_ITEM 0) itemoff 3835 itemsize 160 inode generation 5 transid 0 size 0 nbytes 0 block group 0 mode 40755 links 1 uid 0 gid 0 rdev 0 sequence 0 flags 0x0 atime 1669132761.0 ctime 1669132761.0 mtime 1669132761.0 otime 0.0 item 1 key (256 INODE_REF 256) itemoff 3823 itemsize 12 index 0 name_len 2 item 2 key (258 INODE_ITEM 0) itemoff 3663 itemsize 160 inode generation 1 transid 16 size 733184 nbytes 106496 block group 0 mode 100600 links 0 uid 0 gid 0 rdev 0 sequence 24 flags 0x18 item 3 key (258 EXTENT_DATA 0) itemoff 3595 itemsize 68 generation 16 type 0 inline extent data size 47 ram_bytes 4096 compression 1 [...] item 27 key (18446744073709551611 ORPHAN_ITEM 258) itemoff 2376 itemsize 0 BTRFS error (device loop0): unexpected non-zero offset in file extent item for data reloc inode 258 key offset 0 offset 9277520992061368337 ------------[ cut here ]------------ btrfs_abort_should_print_stack(__error) [CAUSE] The above dump tree shows the first file extent item is inlined, which should make no sense for data reloc inodes, as such inodes just represent where the data extents are in the relocation destination chunk. However the relocation path preallocates space for each block, then dirties them, cluster by cluster. It's possible to have a single block at the beginning of the block group, and no other block in the same cluster. So relocation will preallocate a file extent for that block and dirty the first block. Then memory pressure forces the data reloc inode to be written back, before any other blocks are dirtied/allocated. Finally commit 3eaf5f082c4c ("btrfs: extract inlined creation into a dedicated delalloc helper") changed the sequence of delalloc. Before that commit we always tried NOCOW first, so that dirtied block would be written back into the preallocated space, and appear as a regular extent. But with that commit, we always try inline first, and since compression is forced, we try compressing the first block, and then inline the compressed data, resulting in the above inlined file extent in the data reloc tree. Then the check in get_new_location() will check the file offset, without checking if the file extent is inlined or not, resulting in the above failure. [FIX] Do not allow compression for data reloc inodes. Since data reloc inode sizes are always block aligned, as long as we do not compress, @data_len will always be at least one block, and that will cause can_cow_file_range_inline() to return false, thus no inlined extent will be created.
Severity
No CVSS data available.
Assigner
References
Impacted products
Vendor Product Version CPE status
Linux Linux Affected: 3eaf5f082c4cc71dea70bee23355bf63b24df303 , < 31a62e4ad66313cf1ebaa00c2a17d644a4b87d22 (git)
Affected: 3eaf5f082c4cc71dea70bee23355bf63b24df303 , < ae4316f332e03e628712e9dfb89f2b7d3c70c21a (git)
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Linux Linux Affected: 7.1
Unaffected: 0 , < 7.1 (semver)
Unaffected: 7.1.6 , ≤ 7.1.* (semver)
Unaffected: 7.2 , ≤ * (original_commit_for_fix)
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{
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      "affected": [
        {
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          "product": "Linux",
          "programFiles": [
            "fs/btrfs/btrfs_inode.h"
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        {
          "lang": "en",
          "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nbtrfs: do not try compression for data reloc inodes\n\n[BUG]\nThere is a syzbot report that the check inside get_new_location()\ntriggered:\n\n  BTRFS info (device loop0): found 31 extents, stage: move data extents\n  BTRFS info (device loop0): leaf 8908800 gen 16 total ptrs 28 free space 1676 owner 18446744073709551607\n         item 0 key (256 INODE_ITEM 0) itemoff 3835 itemsize 160\n                 inode generation 5 transid 0 size 0 nbytes 0\n                 block group 0 mode 40755 links 1 uid 0 gid 0\n                 rdev 0 sequence 0 flags 0x0\n                 atime 1669132761.0\n                 ctime 1669132761.0\n                 mtime 1669132761.0\n                 otime 0.0\n         item 1 key (256 INODE_REF 256) itemoff 3823 itemsize 12\n                 index 0 name_len 2\n         item 2 key (258 INODE_ITEM 0) itemoff 3663 itemsize 160\n                 inode generation 1 transid 16 size 733184 nbytes 106496\n                 block group 0 mode 100600 links 0 uid 0 gid 0\n                 rdev 0 sequence 24 flags 0x18\n         item 3 key (258 EXTENT_DATA 0) itemoff 3595 itemsize 68\n                 generation 16 type 0\n                 inline extent data size 47 ram_bytes 4096 compression 1\n  [...]\n         item 27 key (18446744073709551611 ORPHAN_ITEM 258) itemoff 2376 itemsize 0\n  BTRFS error (device loop0): unexpected non-zero offset in file extent item for data reloc inode 258 key offset 0 offset 9277520992061368337\n  ------------[ cut here ]------------\n  btrfs_abort_should_print_stack(__error)\n\n[CAUSE]\nThe above dump tree shows the first file extent item is inlined, which\nshould make no sense for data reloc inodes, as such inodes just\nrepresent where the data extents are in the relocation destination chunk.\n\nHowever the relocation path preallocates space for each block,\nthen dirties them, cluster by cluster.\nIt\u0027s possible to have a single block at the beginning of the block\ngroup, and no other block in the same cluster.\n\nSo relocation will preallocate a file extent for that block and dirty\nthe first block.  Then memory pressure forces the data reloc inode to be\nwritten back, before any other blocks are dirtied/allocated.\n\nFinally commit 3eaf5f082c4c (\"btrfs: extract inlined creation into a dedicated\ndelalloc helper\") changed the sequence of delalloc. Before that commit we\nalways tried NOCOW first, so that dirtied block would be written back into\nthe preallocated space, and appear as a regular extent.\n\nBut with that commit, we always try inline first, and since compression\nis forced, we try compressing the first block, and then inline the\ncompressed data, resulting in the above inlined file extent in the data\nreloc tree.\n\nThen the check in get_new_location() will check the file offset, without\nchecking if the file extent is inlined or not, resulting in the above\nfailure.\n\n[FIX]\nDo not allow compression for data reloc inodes.\n\nSince data reloc inode sizes are always block aligned, as long as we do\nnot compress, @data_len will always be at least one block, and\nthat will cause can_cow_file_range_inline() to return false, thus no\ninlined extent will be created."
        }
      ],
      "providerMetadata": {
        "dateUpdated": "2026-08-17T05:00:07.591Z",
        "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
        "shortName": "Linux"
      },
      "references": [
        {
          "url": "https://git.kernel.org/stable/c/31a62e4ad66313cf1ebaa00c2a17d644a4b87d22"
        },
        {
          "url": "https://git.kernel.org/stable/c/ae4316f332e03e628712e9dfb89f2b7d3c70c21a"
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  "cveMetadata": {
    "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
    "assignerShortName": "Linux",
    "cveId": "CVE-2026-68167",
    "datePublished": "2026-08-10T11:59:35.630Z",
    "dateReserved": "2026-07-30T09:28:09.372Z",
    "dateUpdated": "2026-08-17T05:00:07.591Z",
    "state": "PUBLISHED"
  },
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  "dataVersion": "5.2",
  "vulnerability-lookup:meta": {
    "epss": {
      "cve": "CVE-2026-68167",
      "date": "2026-08-20",
      "epss": "0.00189",
      "percentile": "0.08909"
    },
    "nvd": "{\"cve\":{\"id\":\"CVE-2026-68167\",\"sourceIdentifier\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"published\":\"2026-08-10T13:20:03.233\",\"lastModified\":\"2026-08-17T05:18:17.237\",\"vulnStatus\":\"Received\",\"cveTags\":[],\"descriptions\":[{\"lang\":\"en\",\"value\":\"In the Linux kernel, the following vulnerability has been resolved:\\n\\nbtrfs: do not try compression for data reloc inodes\\n\\n[BUG]\\nThere is a syzbot report that the check inside get_new_location()\\ntriggered:\\n\\n  BTRFS info (device loop0): found 31 extents, stage: move data extents\\n  BTRFS info (device loop0): leaf 8908800 gen 16 total ptrs 28 free space 1676 owner 18446744073709551607\\n         item 0 key (256 INODE_ITEM 0) itemoff 3835 itemsize 160\\n                 inode generation 5 transid 0 size 0 nbytes 0\\n                 block group 0 mode 40755 links 1 uid 0 gid 0\\n                 rdev 0 sequence 0 flags 0x0\\n                 atime 1669132761.0\\n                 ctime 1669132761.0\\n                 mtime 1669132761.0\\n                 otime 0.0\\n         item 1 key (256 INODE_REF 256) itemoff 3823 itemsize 12\\n                 index 0 name_len 2\\n         item 2 key (258 INODE_ITEM 0) itemoff 3663 itemsize 160\\n                 inode generation 1 transid 16 size 733184 nbytes 106496\\n                 block group 0 mode 100600 links 0 uid 0 gid 0\\n                 rdev 0 sequence 24 flags 0x18\\n         item 3 key (258 EXTENT_DATA 0) itemoff 3595 itemsize 68\\n                 generation 16 type 0\\n                 inline extent data size 47 ram_bytes 4096 compression 1\\n  [...]\\n         item 27 key (18446744073709551611 ORPHAN_ITEM 258) itemoff 2376 itemsize 0\\n  BTRFS error (device loop0): unexpected non-zero offset in file extent item for data reloc inode 258 key offset 0 offset 9277520992061368337\\n  ------------[ cut here ]------------\\n  btrfs_abort_should_print_stack(__error)\\n\\n[CAUSE]\\nThe above dump tree shows the first file extent item is inlined, which\\nshould make no sense for data reloc inodes, as such inodes just\\nrepresent where the data extents are in the relocation destination chunk.\\n\\nHowever the relocation path preallocates space for each block,\\nthen dirties them, cluster by cluster.\\nIt\u0027s possible to have a single block at the beginning of the block\\ngroup, and no other block in the same cluster.\\n\\nSo relocation will preallocate a file extent for that block and dirty\\nthe first block.  Then memory pressure forces the data reloc inode to be\\nwritten back, before any other blocks are dirtied/allocated.\\n\\nFinally commit 3eaf5f082c4c (\\\"btrfs: extract inlined creation into a dedicated\\ndelalloc helper\\\") changed the sequence of delalloc. Before that commit we\\nalways tried NOCOW first, so that dirtied block would be written back into\\nthe preallocated space, and appear as a regular extent.\\n\\nBut with that commit, we always try inline first, and since compression\\nis forced, we try compressing the first block, and then inline the\\ncompressed data, resulting in the above inlined file extent in the data\\nreloc tree.\\n\\nThen the check in get_new_location() will check the file offset, without\\nchecking if the file extent is inlined or not, resulting in the above\\nfailure.\\n\\n[FIX]\\nDo not allow compression for data reloc inodes.\\n\\nSince data reloc inode sizes are always block aligned, as long as we do\\nnot compress, @data_len will always be at least one block, and\\nthat will cause can_cow_file_range_inline() to return false, thus no\\ninlined extent will be created.\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"fs/btrfs/btrfs_inode.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"3eaf5f082c4cc71dea70bee23355bf63b24df303\",\"lessThan\":\"31a62e4ad66313cf1ebaa00c2a17d644a4b87d22\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"3eaf5f082c4cc71dea70bee23355bf63b24df303\",\"lessThan\":\"ae4316f332e03e628712e9dfb89f2b7d3c70c21a\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"fs/btrfs/btrfs_inode.h\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"7.1\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"7.1\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1.6\",\"lessThanOrEqual\":\"7.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.2\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/31a62e4ad66313cf1ebaa00c2a17d644a4b87d22\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ae4316f332e03e628712e9dfb89f2b7d3c70c21a\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}",
    "redhat_vex": {
      "aggregate_severity": "Low",
      "current_release_date": "2026-08-13T22:53:25+00:00",
      "cve": "CVE-2026-68167",
      "id": "CVE-2026-68167",
      "initial_release_date": "2026-08-10T00:00:00+00:00",
      "product_status:known_not_affected": "276",
      "source": "Red Hat CSAF VEX",
      "status": "final",
      "title": "kernel: btrfs: do not try compression for data reloc inodes",
      "url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-68167.json",
      "version": "3"
    },
    "suse_vex": {
      "aggregate_severity": "low",
      "current_release_date": "2026-08-13T16:23:52Z",
      "cve": "CVE-2026-68167",
      "id": "CVE-2026-68167",
      "initial_release_date": "2026-08-13T16:23:52Z",
      "product_status:known_affected": "234",
      "product_status:known_not_affected": "62",
      "source": "SUSE CSAF VEX",
      "status": "interim",
      "title": "SUSE CVE CVE-2026-68167",
      "url": "https://ftp.suse.com/pub/projects/security/csaf-vex/cve-2026-68167.json",
      "version": "2"
    }
  }
}



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Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.

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  • Seen: The vulnerability was mentioned, discussed, or observed by the user.
  • Confirmed: The vulnerability has been validated from an analyst's perspective.
  • Published Proof of Concept: A public proof of concept is available for this vulnerability.
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  • Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
  • Not confirmed: The user expressed doubt about the validity of the vulnerability.
  • Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.


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