# CVE-2026-52995: net/rds: zero per-item info buffer before handing it to visitors

> A local unprivileged user can read uninitialized kernel stack memory via RDS info queries, potentially leaking sensitive kernel pointers.

- **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Any signed-in user
- **Attackable:** Local or same network only
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 24 Jun 2026
- **Updated:** 24 Jun 2026
- **Also known as:** BELL-CVE-2026-52995, DEBIAN-CVE-2026-52995, GHSA-735g-xvv4-mj9w, ROOT-OS-DEBIAN-11-CVE-2026-52995, ROOT-OS-DEBIAN-12-CVE-2026-52995, ROOT-OS-UBUNTU-2204-CVE-2026-52995, ROOT-OS-UBUNTU-2404-CVE-2026-52995, UBUNTU-CVE-2026-52995

## What is CVE-2026-52995?

CVE-2026-52995 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.

### Official description

In the Linux kernel, the following vulnerability has been resolved:

net/rds: zero per-item info buffer before handing it to visitors

rds_for_each_conn_info() and rds_walk_conn_path_info() both hand a
caller-allocated on-stack u64 buffer to a per-connection visitor and
then copy the full item_len bytes back to user space via
rds_info_copy() regardless of how much of the buffer the visitor
actually wrote.

rds_ib_conn_info_visitor() and rds6_ib_conn_info_visitor() only
write a subset of their output struct when the underlying
rds_connection is not in state RDS_CONN_UP (src/dst addr, tos, sl
and the two GIDs via explicit memsets). Several u32 fields
(max_send_wr, max_recv_wr, max_send_sge, rdma_mr_max, rdma_mr_size,
cache_allocs) and the 2-byte alignment hole between sl and
cache_allocs remain as whatever stack contents preceded the visitor
call and are then memcpy_to_user()'d out to user space.

struct rds_info_rdma_connection and struct rds6_info_rdma_connection
are the only rds_info_* structs in include/uapi/linux/rds.h that are
not marked __attribute__((packed)), so they have a real alignment
hole. The other info visitors (rds_conn_info_visitor,
rds6_conn_info_visitor, rds_tcp_tc_info, ...) write all fields of
their packed output struct today and are not known to be vulnerable,
but a future visitor that adds a conditional write-path would have
the same bug.

Reproduction on a kernel built without CONFIG_INIT_STACK_ALL_ZERO=y:
a local unprivileged user opens AF_RDS, sets SO_RDS_TRANSPORT=IB,
binds to a local address on an RDMA-capable netdev (rxe soft-RoCE on
any netdev is sufficient), sendto()'s any peer on the same subnet
(fails cleanly but installs an rds_connection in the global hash in
RDS_CONN_CONNECTING), then calls getsockopt(SOL_RDS,
RDS_INFO_IB_CONNECTIONS). The returned 68-byte item contains 26
bytes of stack garbage including kernel text/data pointers:

    0..7   0a 63 00 01 0a 63 00 02     src=10.99.0.1 dst=10.99.0.2
    8..39  00 ...                      gids (memset-zeroed)
    40..47 e0 92 a3 81 ff ff ff ff     kernel pointer (max_send_wr)
    48..55 7f 37 b5 81 ff ff ff ff     kernel pointer (rdma_mr_max)
    56..59 01 00 08 00                 rdma_mr_size (garbage)
    60..61 00 00                       tos, sl
    62..63 00 00                       alignment padding
    64..67 18 00 00 00                 cache_allocs (garbage)

Fix by zeroing the per-item buffer in both rds_for_each_conn_info()
and rds_walk_conn_path_info() before invoking the visitor. This
covers the IPv4/IPv6 IB visitors and hardens all current and future
visitors against the same class of bug.

No functional change for visitors that fully populate their output.

Changes in v2:
- retarget at the net tree (subject prefix "[PATCH net v2]",
  net/rds: prefix in the title)
- pick up Reviewed-by tags from Sharath Srinivasan and
  Allison Henderson

## Which versions are affected by CVE-2026-52995?

It affects 1 product.


Products: Linux kernel.

## How do I fix CVE-2026-52995?

Apply the vendor's patch.

## Is CVE-2026-52995 being exploited?

There is no known exploitation of CVE-2026-52995 in the wild and no public exploit code.

## Other vulnerabilities in Linux kernel

- [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild)
- [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild)
- [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild)
- [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild)
- [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-52995 and fix it if it is affected.

What it is: CVE-2026-52995 is a medium-severity vulnerability in Linux kernel, published on 24 Jun 2026. It can only be exploited from the same machine or local network, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2026-52995 in the wild and no public exploit code.

Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2026-52995/ (Markdown: https://insights.sbomify.com/CVE-2026-52995/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-52995
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-52995
- OSV: https://osv.dev/vulnerability/CVE-2026-52995

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-52995/
Summaries are generated and may contain mistakes; the official description above is the record.