Linux Kernel up to 7.0.12 ones net/rds/ib_send.c rds_ib_send_cqe_handler s_op null pointer dereference

Summaryinfo

A vulnerability was found in Linux Kernel up to 7.0.12 and classified as critical. Impacted is the function rds_ib_send_cqe_handler of the file net/rds/ib_send.c of the component ones. Such manipulation of the argument s_op leads to null pointer dereference. This vulnerability is uniquely identified as CVE-2026-52939. The attack can be launched remotely. No exploit exists. It is suggested to upgrade the affected component.

Detailsinfo

A vulnerability was found in Linux Kernel up to 7.0.12. It has been rated as critical. Affected by this issue is the function rds_ib_send_cqe_handler of the file net/rds/ib_send.c of the component ones. The manipulation of the argument s_op with an unknown input leads to a null pointer dereference vulnerability. Using CWE to declare the problem leads to CWE-476. A NULL pointer dereference occurs when the application dereferences a pointer that it expects to be valid, but is NULL, typically causing a crash or exit. Impacted is availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion rds_ib_xmit_atomic() always programs a masked atomic opcode (IB_WR_MASKED_ATOMIC_CMP_AND_SWP or IB_WR_MASKED_ATOMIC_FETCH_AND_ADD) for every RDS atomic cmsg. But the completion-side switch in rds_ib_send_unmap_op() only handles the non-masked opcodes, so a masked atomic completion falls through to default and returns rm == NULL while send->s_op is left set. rds_ib_send_cqe_handler() then dereferences the NULL rm via rm->m_final_op, oopsing in softirq context. An unprivileged AF_RDS sendmsg() of an atomic cmsg over an active RDS/IB connection triggers it; on hardware that natively accepts masked atomics (mlx4, mlx5) no extra setup is needed. RDS/IB: rds_ib_send_unmap_op: unexpected opcode 0xd in WR! Oops: general protection fault [#1] SMP KASAN KASAN: null-ptr-deref in range [0x0000000000000190-0x0000000000000197] RIP: rds_ib_send_cqe_handler+0x25c/0xb10 (net/rds/ib_send.c:282) Call Trace: rds_ib_send_cqe_handler (net/rds/ib_send.c:282) poll_scq (net/rds/ib_cm.c:274) rds_ib_tasklet_fn_send (net/rds/ib_cm.c:294) tasklet_action_common (kernel/softirq.c:943) handle_softirqs (kernel/softirq.c:573) run_ksoftirqd (kernel/softirq.c:479) Kernel panic - not syncing: Fatal exception in interrupt Handle the masked atomic opcodes in the same case as the non-masked ones: they map to the same struct rds_message.atomic union member, so the existing container_of()/rds_ib_send_unmap_atomic() body is correct for them.

The advisory is available at git.kernel.org. This vulnerability is handled as CVE-2026-52939 since 06/09/2026. The exploitation is known to be difficult. The attack may be launched remotely. Technical details are known, but there is no available exploit. The structure of the vulnerability defines a possible price range of USD $0-$5k at the moment (estimation calculated on 06/24/2026).

Upgrading to version 5.10.259, 5.15.210, 6.1.176, 6.6.143, 6.12.94, 6.18.36 or 7.0.13 eliminates this vulnerability. Applying the patch a0148342badd8c9b2e46551766a27cb76c82e715/4dd262f875e87653df50b138de1390ab0628e6b7/6e4615164d185a26badb2f376a2449f4d174a5f0/0f22412a2f4fbbe0251c132abee045d15a90e5b6/0f7baa82a24813cdad0b06a6f8f07e4824af5ed5/dcf458120add64c96a6ef5cf719340453f6e6abf/4fd34669558085bcb589aa2078a13b0ca79e360d/34080db3e70ddf94c38512ad2331e3c3afca6cc1 is able to eliminate this problem. The bugfix is ready for download at git.kernel.org. The best possible mitigation is suggested to be upgrading to the latest version.

The vulnerability is also documented in the vulnerability database at EUVD (EUVD-2026-38709). If you want to get best quality of vulnerability data, you may have to visit VulDB.

Productinfo

Type

• Operating System

Vendor

• Linux

Name

• Kernel

Version

• 5.10.258
• 5.15.209
• 6.1.175
• 6.6.142
• 6.12.0
• 6.12.1
• 6.12.2
• 6.12.3
• 6.12.4
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• 6.12.87
• 6.12.88
• 6.12.89
• 6.12.90
• 6.12.91
• 6.12.92
• 6.12.93
• 6.18.0
• 6.18.1
• 6.18.2
• 6.18.3
• 6.18.4
• 6.18.5
• 6.18.6
• 6.18.7
• 6.18.8
• 6.18.9
• 6.18.10
• 6.18.11
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• 6.18.13
• 6.18.14
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• 6.18.31
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• 6.18.33
• 6.18.34
• 6.18.35
• 7.0.0
• 7.0.1
• 7.0.2
• 7.0.3
• 7.0.4
• 7.0.5
• 7.0.6
• 7.0.7
• 7.0.8
• 7.0.9
• 7.0.10
• 7.0.11
• 7.0.12

License

• open-source

Website

• Vendor: https://www.kernel.org/

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Entryinfo

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