net/rds: fix NULL deref in rds_ib_send_cqe_handler() on masked atomic completion

MITRE NVD CVE.ORG JSON API

Summary

CVECVE-2026-52939
StatePUBLISHED
AssignerLinux
Source PriorityCVE Program / NVD first with legacy fallback
Published2026-06-24 08:16:24 UTC
Updated2026-07-08 19:14:19 UTC
DescriptionIn 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: <IRQ> 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) </IRQ> 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.

Risk And Classification

Primary CVSS: v3.1 5.5 MEDIUM from [email protected]

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

EPSS: 0.001140000 probability, percentile 0.017490000 (date 2026-07-09)

Problem Types: CWE-476

CVSS v3.1 Breakdown

Attack Vector
Local
Attack Complexity
Low
Privileges Required
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

NVD Known Affected Configurations (CPE 2.3)

TypeVendorProductVersionUpdateEditionLanguage
Operating System Linux Linux Kernel All All All All

Vendor Declared Affected Products

SourceVendorProductVersionPlatforms
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c a0148342badd8c9b2e46551766a27cb76c82e715 git Not specified
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c 4dd262f875e87653df50b138de1390ab0628e6b7 git Not specified
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c 6e4615164d185a26badb2f376a2449f4d174a5f0 git Not specified
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c 0f22412a2f4fbbe0251c132abee045d15a90e5b6 git Not specified
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c 0f7baa82a24813cdad0b06a6f8f07e4824af5ed5 git Not specified
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c dcf458120add64c96a6ef5cf719340453f6e6abf git Not specified
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c 4fd34669558085bcb589aa2078a13b0ca79e360d git Not specified
CNA Linux Linux affected 20c72bd5f5f902e5a8745d51573699605bf8d21c 34080db3e70ddf94c38512ad2331e3c3afca6cc1 git Not specified
CNA Linux Linux affected 2.6.37 Not specified
CNA Linux Linux unaffected 2.6.37 semver Not specified
CNA Linux Linux unaffected 5.10.259 5.10.* semver Not specified
CNA Linux Linux unaffected 5.15.210 5.15.* semver Not specified
CNA Linux Linux unaffected 6.1.176 6.1.* semver Not specified
CNA Linux Linux unaffected 6.6.143 6.6.* semver Not specified
CNA Linux Linux unaffected 6.12.94 6.12.* semver Not specified
CNA Linux Linux unaffected 6.18.36 6.18.* semver Not specified
CNA Linux Linux unaffected 7.0.13 7.0.* semver Not specified
CNA Linux Linux unaffected 7.1 * original_commit_for_fix Not specified

References

ReferenceSourceLinkTags
git.kernel.org/stable/c/4dd262f875e87653df50b138de1390ab0628e6b7 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/34080db3e70ddf94c38512ad2331e3c3afca6cc1 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/0f22412a2f4fbbe0251c132abee045d15a90e5b6 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/4fd34669558085bcb589aa2078a13b0ca79e360d 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/6e4615164d185a26badb2f376a2449f4d174a5f0 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/dcf458120add64c96a6ef5cf719340453f6e6abf 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/0f7baa82a24813cdad0b06a6f8f07e4824af5ed5 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
git.kernel.org/stable/c/a0148342badd8c9b2e46551766a27cb76c82e715 416baaa9-dc9f-4396-8d5f-8c081fb06d67 git.kernel.org Patch
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