CVE-2026-45856

Kernel-heap disclosure via undersized RDMA work request

Published May 27, 2026 · Updated May 27, 2026

Out-of-bounds read in the Linux Kernel RDMA uverbs subsystem allows local users to disclose kernel heap data through a device write. ib_uverbs_post_send() trusts the user-controlled cmd.wqe_size when allocating a buffer, then reads fixed struct ib_uverbs_send_wr fields beyond an undersized allocation. Access to /dev/infiniband/uverbs* is required; a small value exposes kernel-heap contents, while a huge value can panic kernels configured with panic_on_warn.

CVSS severity7.1
High
EPSS probability0.17%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Out-of-bounds read in the Linux Kernel RDMA uverbs subsystem allows local users to disclose kernel heap data through a device write. ib_uverbs_post_send() trusts the user-controlled cmd.wqe_size when allocating a buffer, then reads fixed struct ib_uverbs_send_wr fields beyond an undersized allocation. Access to /dev/infiniband/uverbs* is required; a small value exposes kernel-heap contents, while a huge value can panic kernels configured with panic_on_warn.

The record

CVE
CVE-2026-45856
Published
May 27, 2026
Updated
May 27, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. May 27, 2026CVE publishedPublication date reported by the CVE source.
  2. May 27, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

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Is a vulnerable build present?

Compare these published version ranges with your installed build and any vendor patches.

  1. Affected versionversion=5.0
  2. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <01c9b152647dc70dc06a4a2eff86ebb3b3c76075
  3. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0
  4. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <9b5ac1c15334d46c0dbd49d64a2257b929500163
  5. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7
  6. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <bef70ff9841990658610512b4a18e4a88c9b4df6
  7. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <bf1feed1a7886af945f92890493aefd2b5c9928a
  8. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <bf4454da8b1e712714628c0a0d6e7845bb40790a
  9. Affected versionversion=c3bea3d2dc5358e05541527283279102383b0231 <d533425ac1f2925b4fc3e4ed9b9d72362cb23475

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=5.0; version=c3bea3d2dc5358e05541527283279102383b0231 <01c9b152647dc70dc06a4a2eff86ebb3b3c76075; version=c3bea3d2dc5358e05541527283279102383b0231 <1956f0a74ccf5dc9c3ef717f2985c3ed3400aab0; version=c3bea3d2dc5358e05541527283279102383b0231 <9b5ac1c15334d46c0dbd49d64a2257b929500163; version=c3bea3d2dc5358e05541527283279102383b0231 <9c15ec4cd4e7f57c6bbcb4e73e99290f150dd2a7; version=c3bea3d2dc5358e05541527283279102383b0231 <bef70ff9841990658610512b4a18e4a88c9b4df6; version=c3bea3d2dc5358e05541527283279102383b0231 <bf1feed1a7886af945f92890493aefd2b5c9928a; version=c3bea3d2dc5358e05541527283279102383b0231 <bf4454da8b1e712714628c0a0d6e7845bb40790a; version=c3bea3d2dc5358e05541527283279102383b0231 <d533425ac1f2925b4fc3e4ed9b9d72362cb23475

Published CVSS scores

7.1Linux Kernel CVE TeamCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.

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No observations available

Sep 9, 2026Sep 15, 2026
Latest reporting daySep 15, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

No sourced classifications are available.

Public exploit references

No public exploit references are available in this record.

Labels summarize the accepted research assessment. They do not indicate a test against your environment.

Technologies

Your stack

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Your stack

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