vsock: fix buffer size clamping order

Summary

In the Linux kernel, the following vulnerability has been resolved: vsock: fix buffer size clamping order In vsock_update_buffer_size(), the buffer size was being clamped to the maximum first, and then to the minimum. If a user sets a minimum buffer size larger than the maximum, the minimum check overrides the maximum check, inverting the constraint. This breaks the intended socket memory boundaries by allowing the vsk->buffer_size to grow beyond the configured vsk->buffer_max_size. Fix this by checking the minimum first, and then the maximum. This ensures the buffer size never exceeds the buffer_max_size.

Timeline

1. May 28, 2026, 9:40 AM UTCCVE published
2. Oct 15, 2026, 1:21 AM UTCRecord last updated

Affected versions

• Linux Linux

  From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in f6ec135941d2c1c2dbb87b5ce1783f4f6ac6ccca; From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in caf11dfea5233a69298a1c448bbf8d1639c80536; From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in 01ef69785dc3162f588a361ab770b1e312800188; From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in a998a7e250bf976539e05a00ec64a81292afecaa; From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in 310da27932dd0afe7ce7456dfe1f0814c3301f41; From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in 2602f7bb5818e92315feeaeb71d8ce4d5c9ab160; From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in 0b68881501460c3761f196469e1e503218c5e536; From b9f2b0ffde0c9b666b2b1672eb468b8f805a9b97 · fixed in d114bfdc9b76bf93b881e195b7ec957c14227bab

• Linux Linux

  5.5

• KernelLinux

  From 5.5.0 · fixed in 5.10.258; From 5.11.0 · fixed in 5.15.209; From 5.16.0 · fixed in 6.1.175; From 6.2.0 · fixed in 6.6.140; From 6.7.0 · fixed in 6.12.90; From 6.13.0 · fixed in 6.18.32; From 6.19.0 · fixed in 7.0.9

References 8