CVE-2021-47138

Local memory disclosure and crash via invalid TID

Published Mar 25, 2024 · Updated May 11, 2026

Out-of-bounds memory access in the Linux cxgb4 driver allows local users to disclose kernel memory or crash the host. During filter cleanup in cxgb4_filter.c, the driver reads the server TID base from a hardware register after an adapter failure and uses the invalid value for an out-of-bounds access. Exploitation requires low-privileged local access and a Chelsio cxgb4 adapter in a bad state, such as after a fatal PCIe AER error.

CVSS severity7.1
High
EPSS probability0.24%
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 memory access in the Linux cxgb4 driver allows local users to disclose kernel memory or crash the host. During filter cleanup in cxgb4_filter.c, the driver reads the server TID base from a hardware register after an adapter failure and uses the invalid value for an out-of-bounds access. Exploitation requires low-privileged local access and a Chelsio cxgb4 adapter in a bad state, such as after a fatal PCIe AER error.

The record

CVE
CVE-2021-47138
Published
Mar 25, 2024
Updated
May 11, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-787
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Mar 25, 2024CVE publishedPublication date reported by the CVE source.
  2. May 11, 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=5.2
  2. Affected versionversion=b1a79360ee862f8ada4798ad2346fa45bb41b527 <02f03883fdb10ad7e66717c70ea163a8d27ae6e7
  3. Affected versionversion=b1a79360ee862f8ada4798ad2346fa45bb41b527 <0bf49b3c8d8b3a43ce09f1b2db70e5484d31fcdf
  4. Affected versionversion=b1a79360ee862f8ada4798ad2346fa45bb41b527 <285207a558ab456aa7d8aa877ecc7e91fcc51710
  5. Affected versionversion=b1a79360ee862f8ada4798ad2346fa45bb41b527 <88c380df84fbd03f9b137c2b9d0a44b9f2f553b0

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=5.2; version=b1a79360ee862f8ada4798ad2346fa45bb41b527 <02f03883fdb10ad7e66717c70ea163a8d27ae6e7; version=b1a79360ee862f8ada4798ad2346fa45bb41b527 <0bf49b3c8d8b3a43ce09f1b2db70e5484d31fcdf; version=b1a79360ee862f8ada4798ad2346fa45bb41b527 <285207a558ab456aa7d8aa877ecc7e91fcc51710; version=b1a79360ee862f8ada4798ad2346fa45bb41b527 <88c380df84fbd03f9b137c2b9d0a44b9f2f553b0

Published CVSS scores

7.1NIST NVDCVSS: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 10, 2026Sep 16, 2026
Latest reporting daySep 16, 2026
Latest daily unique IPsUnavailable
Prior 30-day averageUnavailable
SourceShadowserver honeypots (KEV)
Vectorlocal
Privilegesauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-787Out-of-bounds Write

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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