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Linux KernelOperating system · Linux

CVE-2026-52995

MEDIUM · 5.5 CVSS v3.1 Published 2026-06-24
Fix available
A fix is available. Upgrade to 5.10.258 / 5.15.209 or later.
See remediation →
57/100
Remediation priority · Elevated
Zero-click Patch available 8 weeks old

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

NVD · unedited
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

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

dbcve analysis · high confidence

A kernel stack information disclosure vulnerability in Linux RDS (Reliable Datagram Sockets) where the IB connection info visitor functions only partially zero their output buffer when connections aren't in RDS_CONN_UP state. Uninitialized fields (max_send_wr, max_recv_wr, max_send_sge, rdma_mr_max, rdma_mr_size, cache_allocs) and an alignment hole are copied to userspace via getsockopt(RDS_INFO_IB_CONNECTIONS), leaking kernel stack contents including kernel pointers.

MitigationApply the upstream kernel patch that zeros the per-item buffer before invoking visitors in rds_for_each_conn_info() and rds_walk_conn_path_info(). For older kernels, ensure CONFIG_INIT_STACK_ALL_ZERO=y is enabled as a partial mitigation (though it doesn't eliminate the bug entirely).

Verify against the referenced sources before acting — the references below are authoritative for this CVE, this summary is not.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

NVD · CPE data
Linux KernelOperating system
Affected:>= 2.6.30, < 5.10.258>= 5.11, < 5.15.209>= 5.16, < 6.1.175>= 6.2, < 6.6.141>= 6.7, < 6.12.91>= 6.13, < 6.18.33>= 6.19, < 7.0.10

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

From the vector
Attack vector
Local
Complexity
Low
Privileges
Low
User interaction
None
Scope
Unchanged
Confidentiality
None
Integrity
None
Availability
High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Am I affected? How to checkSteps we derive from the advisory and the affected-version data, so you can decide whether this CVE reaches your setup. They are a guide, not a scan — your own configuration is the authority.

dbcve checks

Work through these to decide whether this CVE applies to you.

  1. Check if RDS kernel module is loaded
    Run 'lsmod | grep rds' or check /proc/modules for 'rds' to see if the RDS module is loaded
    Affected if The RDS module is loaded and the kernel version falls within the affected ranges listed in the CVE
  2. Verify kernel version against affected ranges
    Run 'uname -r' and compare the kernel version to: >= 2.6.30 and < 5.10.258; >= 5.11 and < 5.15.209; >= 5.16 and < 6.1.175; >= 6.2 and < 6.6.141; >= 6.7 and < 6.12.91; >= 6.13 and < 6.18.33; >= 6.19 and < 7.0.10
    Affected if The installed kernel version matches any of the affected version ranges
  3. Check if RDS protocol is configured or active
    Look for /sys/module/rds/ or check if RDS sockets can be created using 'ss -a' or 'netstat' filters for RDS protocol (protocol number 21), or attempt to create a socket with socket(AF_RDS, ...)
    Affected if RDS protocol support is enabled in the kernel (built-in or module) and version is affected
  4. Detect RDS_INFO_IB_CONNECTIONS socket option usage
    Monitor system calls using 'auditctl' rules for getsockopt with optname RDS_INFO_IB_CONNECTIONS, or trace using 'strace' on processes that may query RDS connection info, or inspect /proc/*/fd for open RDS sockets
    Affected if Any process invokes getsockopt with RDS_INFO_IB_CONNECTIONS on an affected kernel with RDS enabled
  5. Check for non-up RDS connections
    Inspect /proc/net/rds or use 'cat /sys/kernel/debug/rds/connections' (if debugfs is mounted) to list RDS connections and their states
    Affected if Any RDS over InfiniBand (RDS-RDMA) connections exist in a state other than RDS_CONN_UP while getsockopt RDS_INFO_IB_CONNECTIONS is called

You are affected if you are running a Linux kernel version within the affected ranges with RDS protocol enabled, and any RDS InfiniBand connection exists in a non-up state while userspace queries connection info via getsockopt(RDS_INFO_IB_CONNECTIONS).

Generated from the published advisory. Verify against your own configuration.

Check your environment

Paste your version and any relevant configuration and it will be compared against the affected criteria above. Do not include secrets or credentials.

AI-assisted, checked against the advisory. Informational, not a guarantee.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

dbcve · scoped
Upgrade available Upgrade to 5.10.258 / 5.15.209 / 6.1.175 or later
Fixed in 5.10.2585.15.2096.1.175
Vendor patch git.kernel.org →
Interim mitigation

Apply the upstream kernel patch that zeros the per-item buffer before invoking visitors in rds_for_each_conn_info() and rds_walk_conn_path_info(). For older kernels, ensure CONFIG_INIT_STACK_ALL_ZERO=y is enabled as a partial mitigation (though it doesn't eliminate the bug entirely).

Recommended fix High confidence

Upgrade to Linux kernel 5.10.258, 5.15.209, 6.1.175, or 6.6.141 (or later stable release) depending on your current branch

  1. 1. Identify the current kernel version using `uname -r`
  2. 2. Determine which stable branch your current kernel version belongs to (e.g., 5.10.x, 5.15.x, 6.1.x, or 6.2.x+)
  3. 3. Upgrade to the corresponding fixed release: 5.10.258, 5.15.209, 6.1.175, or 6.6.141 respectively
  4. 4. For Ubuntu/Debian: use `apt update && apt upgrade` or install the specific linux-image package for the fixed version
  5. 5. For RHEL/CentOS: use `yum update` or install the corresponding kernel RPM
  6. 6. For other distributions: obtain the fixed kernel from your vendor or compile from source at git.kernel.org using the tagged release
  7. 7. Reboot into the updated kernel
  8. 8. Verify the fix by checking that kernel pointers are no longer leaked when calling getsockopt(SOL_RDS, RDS_INFO_IB_CONNECTIONS)
Caveat Standard kernel upgrade risks apply - ensure compatibility with system hardware and drivers before deploying in production

Generated from the published advisory — verify against the referenced sources before acting.

Fix this in Linux Kernel Scoped from the published advisory
  • Consultation1.0 h
  • Implementation1.0 h
  • Testing2.0 h
  • Review / QA1.0 h
5.0 hours of engineering $860
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References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2026-52995 in production — separate from our analysis above.

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