PT-2026-43810 · Linux · Linux

Published

2026-05-27

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Updated

2026-05-27

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CVE-2026-45943

None

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In the Linux kernel, the following vulnerability has been resolved:
erofs: fix inline data read failure for ztailpacking pclusters
Compressed folios for ztailpacking pclusters must be valid before adding these pclusters to I/O chains. Otherwise, z erofs decompress pcluster() may assume they are already valid and then trigger a NULL pointer dereference.
It is somewhat hard to reproduce because the inline data is in the same block as the tail of the compressed indexes, which are usually read just before. However, it may still happen if a fatal signal arrives while read mapping folio() is running, as shown below:
erofs: (device dm-1): z erofs pcluster begin: failed to get inline data -4 Unable to handle kernel NULL pointer dereference at virtual address 0000000000000008
...
pc : z erofs decompress queue+0x4c8/0xa14 lr : z erofs decompress queue+0x160/0xa14 sp : ffffffc08b3eb3a0 x29: ffffffc08b3eb570 x28: ffffffc08b3eb418 x27: 0000000000001000 x26: ffffff8086ebdbb8 x25: ffffff8086ebdbb8 x24: 0000000000000001 x23: 0000000000000008 x22: 00000000fffffffb x21: dead000000000700 x20: 00000000000015e7 x19: ffffff808babb400 x18: ffffffc089edc098 x17: 00000000c006287d x16: 00000000c006287d x15: 0000000000000004 x14: ffffff80ba8f8000 x13: 0000000000000004 x12: 00000006589a77c9 x11: 0000000000000015 x10: 0000000000000000 x9 : 0000000000000000 x8 : 0000000000000000 x7 : 0000000000000000 x6 : 000000000000003f x5 : 0000000000000040 x4 : ffffffffffffffe0 x3 : 0000000000000020 x2 : 0000000000000008 x1 : 0000000000000000 x0 : 0000000000000000 Call trace: z erofs decompress queue+0x4c8/0xa14 z erofs runqueue+0x908/0x97c z erofs read folio+0x128/0x228 filemap read folio+0x68/0x128 filemap get pages+0x44c/0x8b4 filemap read+0x12c/0x5b8 generic file read iter+0x4c/0x15c do iter readv writev+0x188/0x1e0 vfs iter read+0xac/0x1a4 backing file read iter+0x170/0x34c ovl read iter+0xf0/0x140 vfs read+0x28c/0x344 ksys read+0x80/0xf0 arm64 sys read+0x24/0x34 invoke syscall+0x60/0x114 el0 svc common+0x88/0xe4 do el0 svc+0x24/0x30 el0 svc+0x40/0xa8 el0t 64 sync handler+0x70/0xbc el0t 64 sync+0x1bc/0x1c0
Fix this by reading the inline data before allocating and adding the pclusters to the I/O chains.

Related Identifiers

CVE-2026-45943

Affected Products

Linux