squashfs: Add dictionary size range check to prevent shift-out-of-bounds
In the Linux kernel, the following vulnerability has been resolved: squashfs: Add dictionary size range check to prevent shift-out-of-bounds When an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size is 0) is mounted, and performs shift operations using dictionarysize, the shift exponent is -1, causing a shift-out-of-bounds. Detail as below: squashfs_comp_opts(msblk, buffer, length) squashfs_xz_comp_opts() if (comp_opts) n = ffs(opts->dict_size) - 1;<----opts->dict_size=0, n=-1 if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + (1 << (n + 1))) <----shift-out-of-bounds Fix it by adding a dictionary size range check before the shift operation.
- Products
- Kernel
- Affected versions
- Not specified
- Fixed versions
- 5.10.271, 5.15.222, 6.1.189, 6.12.112, 6.18.55, 6.6.158, 7.2.9
- CVEs
- CVE-2026-98636
- Confirmed fixed CVEs
- Not specified
- Updated in this feed
- 8 Nov 2026, 02:51 UTC · Revision 1
Source evidence
squashfs: Add dictionary size range check to prevent shift-out-of-bounds
core-osv · Original sourcePublished 18 Oct 2026, 15:20 UTC
In the Linux kernel, the following vulnerability has been resolved: squashfs: Add dictionary size range check to prevent shift-out-of-bounds When an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size is 0) is mounted, and performs shift operations using dictionarysize, the shift exponent is -1, causing a shift-out-of-bounds. Detail as below: squashfs_comp_opts(msblk, buffer, length) squashfs_xz_comp_opts() if (comp_opts) n = ffs(opts->dict_size) - 1;<----opts->dict_size=0, n=-1 if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + (1 << (n + 1))) <----shift-out-of-bounds Fix it by adding a dictionary size range check before the shift operation.
osv:CVE-2026-98636
Kernel
Fixed versions: 5.10.271, 5.15.222, 6.1.189, 6.6.158, 6.12.112, 6.18.55, 7.2.9
Complete source record
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"id": "e2dfa7be8eeb664aaccbe1657e83a0d840980c1bae405910f18f9f5dcf6c58e8",
"url": "https://osv.dev/vulnerability/CVE-2026-98636",
"method": "structured",
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"title": "squashfs: Add dictionary size range check to prevent shift-out-of-bounds",
"summary": "In the Linux kernel, the following vulnerability has been resolved: squashfs: Add dictionary size range check to prevent shift-out-of-bounds When an abnormal SquashFS image (COMP_OPTS flag is 1 but dictionary size is 0) is mounted, and performs shift operations using dictionarysize, the shift exponent is -1, causing a shift-out-of-bounds. Detail as below: squashfs_comp_opts(msblk, buffer, length) squashfs_xz_comp_opts() if (comp_opts) n = ffs(opts->dict_size) - 1;<----opts->dict_size=0, n=-1 if (opts->dict_size != (1 << n) && opts->dict_size != (1 << n) + (1 << (n + 1))) <----shift-out-of-bounds Fix it by adding a dictionary size range check before the shift operation.",
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"modified": "2026-10-28T02:30:53.128632639Z",
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"source_id": "core-osv",
"document_id": 521952,
"published_at": "2026-10-18T15:20:07.184+00:00"
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