In the Linux kernel, the following vulnerability has been resolved:
io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()
sqe->len is __u32 but gets stored into sr->len which is int. When
userspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF),
sr->len overflows to a negative value. This negative value propagates
through the bundle recv/send path:
1. io_recv(): sel.val = sr->len (ssize_t gets -1)
2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets
0xFFFFFFFFFFFFFFFF)
3. io_ring_buffers_peek(): buf->len is not clamped because max_len
is astronomically large
4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs()
5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1,
causing ret to increase instead of decrease, creating an
infinite loop that reads past the allocated iov[] array
This results in a slab-out-of-bounds read in io_bundle_nbufs() from
the kmalloc-64 slab, as nbufs increments past the allocated iovec
entries.
BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160
Read of size 8 at addr ffff888100ae05c8 by task exp/145
Call Trace:
io_bundle_nbufs+0x128/0x160
io_recv_finish+0x117/0xe20
io_recv+0x2db/0x1160
Fix this by rejecting negative sr->len values early in both
io_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32,
any value > INT_MAX indicates overflow and is not a valid length.
io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs()
sqe->len is __u32 but gets stored into sr->len which is int. When
userspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF),
sr->len overflows to a negative value. This negative value propagates
through the bundle recv/send path:
1. io_recv(): sel.val = sr->len (ssize_t gets -1)
2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets
0xFFFFFFFFFFFFFFFF)
3. io_ring_buffers_peek(): buf->len is not clamped because max_len
is astronomically large
4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs()
5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1,
causing ret to increase instead of decrease, creating an
infinite loop that reads past the allocated iov[] array
This results in a slab-out-of-bounds read in io_bundle_nbufs() from
the kmalloc-64 slab, as nbufs increments past the allocated iovec
entries.
BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160
Read of size 8 at addr ffff888100ae05c8 by task exp/145
Call Trace:
io_bundle_nbufs+0x128/0x160
io_recv_finish+0x117/0xe20
io_recv+0x2db/0x1160
Fix this by rejecting negative sr->len values early in both
io_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32,
any value > INT_MAX indicates overflow and is not a valid length.
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | |||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
|
|||||||||||||||||||||
| Linux | Linux | affected |
|
No data.
No data.
No data.
Advisories
No advisories yet.
Fixes
Solution
No solution given by the vendor.
Workaround
No workaround given by the vendor.
References
History
Fri, 01 May 2026 14:45:00 +0000
| Type | Values Removed | Values Added |
|---|---|---|
| Description | In the Linux kernel, the following vulnerability has been resolved: io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs() sqe->len is __u32 but gets stored into sr->len which is int. When userspace passes sqe->len values exceeding INT_MAX (e.g. 0xFFFFFFFF), sr->len overflows to a negative value. This negative value propagates through the bundle recv/send path: 1. io_recv(): sel.val = sr->len (ssize_t gets -1) 2. io_recv_buf_select(): arg.max_len = sel->val (size_t gets 0xFFFFFFFFFFFFFFFF) 3. io_ring_buffers_peek(): buf->len is not clamped because max_len is astronomically large 4. iov[].iov_len = 0xFFFFFFFF flows into io_bundle_nbufs() 5. io_bundle_nbufs(): min_t(int, 0xFFFFFFFF, ret) yields -1, causing ret to increase instead of decrease, creating an infinite loop that reads past the allocated iov[] array This results in a slab-out-of-bounds read in io_bundle_nbufs() from the kmalloc-64 slab, as nbufs increments past the allocated iovec entries. BUG: KASAN: slab-out-of-bounds in io_bundle_nbufs+0x128/0x160 Read of size 8 at addr ffff888100ae05c8 by task exp/145 Call Trace: io_bundle_nbufs+0x128/0x160 io_recv_finish+0x117/0xe20 io_recv+0x2db/0x1160 Fix this by rejecting negative sr->len values early in both io_sendmsg_prep() and io_recvmsg_prep(). Since sqe->len is __u32, any value > INT_MAX indicates overflow and is not a valid length. | |
| Title | io_uring/net: fix slab-out-of-bounds read in io_bundle_nbufs() | |
| First Time appeared |
Linux
Linux linux Kernel |
|
| CPEs | cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | |
| Vendors & Products |
Linux
Linux linux Kernel |
|
| References |
|
Projects
Sign in to view the affected projects.
MITRE
Status: PUBLISHED
Assigner: Linux
Published:
Updated: 2026-05-01T14:15:02.903Z
Reserved: 2026-03-09T15:48:24.140Z
Link: CVE-2026-31774
Vulnrichment
No data.
NVD
Status : Awaiting Analysis
Published: 2026-05-01T15:16:40.720
Modified: 2026-05-01T15:24:14.893
Link: CVE-2026-31774
Redhat
No data.
OpenCVE Enrichment
No data.
Weaknesses
No weakness.