CVE-2026-31774 (GCVE-0-2026-31774)
Vulnerability from cvelistv5
Published
2026-05-01 14:15
Modified
2026-10-19 19:06
Severity ?
VLAI Severity ?
EPSS score ?
Summary
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.
References
| URL | Tags | |
|---|---|---|
Impacted products
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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