CVE-2021-46905

Local system crash via post-unregister table access

Published Feb 25, 2024 · Updated May 23, 2026

NULL-pointer dereference in the Linux kernel hso USB serial driver allows local users to crash the system during device disconnection. The disconnect path calls hso_serial_tty_unregister() and then accesses the serial device table with the released minor, unconditionally dereferencing a NULL entry. Reachability requires disconnection of an hso USB serial device, and the resulting kernel fault crashes the host without reading or altering data.

CVSS severity5.5
Medium
EPSS probability0.26%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

NULL-pointer dereference in the Linux kernel hso USB serial driver allows local users to crash the system during device disconnection. The disconnect path calls hso_serial_tty_unregister() and then accesses the serial device table with the released minor, unconditionally dereferencing a NULL entry. Reachability requires disconnection of an hso USB serial device, and the resulting kernel fault crashes the host without reading or altering data.

The record

CVE
CVE-2021-46905
Published
Feb 25, 2024
Updated
May 23, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
CWE-476, T1499
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Feb 25, 2024CVE publishedPublication date reported by the CVE source.
  2. May 23, 2026Record updatedLatest update available in the CVE record.

Exploitability

Present is not the same as exploitable

Compare your product and version with the public record. A matching version still requires validation against your environment.

Is a vulnerable build present?

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

  1. Affected versionversion=145c89c441d27696961752bf51b323f347601bee <0c71d4c89559f72cec2592d078681a843bce570e
  2. Affected versionversion=388d05f70f1ee0cac4a2068fd295072f1a44152a <0f000005da31f6947f843ce6b3e3a960540c6e00
  3. Affected versionversion=4.19.187 <4.19.189
  4. Affected versionversion=4a2933c88399c0ebc738db39bbce3ae89786d723 <d7fad2ce15bdbbd0fec3ebe999fd7cab2267f53e
  5. Affected versionversion=5.10.30 <5.10.33
  6. Affected versionversion=5.11.14 <5.11.17
  7. Affected versionversion=5.12
  8. Affected versionversion=5.4.112 <5.4.115
  9. Affected versionversion=8a12f8836145ffe37e9c8733dce18c22fb668b66 <2ad5692db72874f02b9ad551d26345437ea4f7f3
  10. Affected versionversion=8a12f8836145ffe37e9c8733dce18c22fb668b66 <41c44e1f3112d7265dae522c026399b2a42d19ef
  11. Affected versionversion=92028d7a31e55d53e41cff679156b9432cffcb36 <5c17cfe155d21954b4c7e2a78fa771cebcd86725
  12. Affected versionversion=a462067d7c8e6953a733bf5ade8db947b1bb5449 <5871761c5f0f20d6e98bf3b6bd7486d857589554
  13. Affected versionversion=caf5ac93b3b5d5fac032fc11fbea680e115421b4 <24b699bea7553fc0b98dad9d864befb6005ac7f1
  14. Affected versionversion=dc195928d7e4ec7b5cfc6cd10dc4c8d87a7c72ac <90642ee9eb581a13569b1c0bd57e85d962215273

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=145c89c441d27696961752bf51b323f347601bee <0c71d4c89559f72cec2592d078681a843bce570e; version=388d05f70f1ee0cac4a2068fd295072f1a44152a <0f000005da31f6947f843ce6b3e3a960540c6e00; version=4.19.187 <4.19.189; version=4a2933c88399c0ebc738db39bbce3ae89786d723 <d7fad2ce15bdbbd0fec3ebe999fd7cab2267f53e; version=5.10.30 <5.10.33; version=5.11.14 <5.11.17; version=5.12; version=5.4.112 <5.4.115; version=8a12f8836145ffe37e9c8733dce18c22fb668b66 <2ad5692db72874f02b9ad551d26345437ea4f7f3; version=8a12f8836145ffe37e9c8733dce18c22fb668b66 <41c44e1f3112d7265dae522c026399b2a42d19ef; version=92028d7a31e55d53e41cff679156b9432cffcb36 <5c17cfe155d21954b4c7e2a78fa771cebcd86725; version=a462067d7c8e6953a733bf5ade8db947b1bb5449 <5871761c5f0f20d6e98bf3b6bd7486d857589554; version=caf5ac93b3b5d5fac032fc11fbea680e115421b4 <24b699bea7553fc0b98dad9d864befb6005ac7f1; version=dc195928d7e4ec7b5cfc6cd10dc4c8d87a7c72ac <90642ee9eb581a13569b1c0bd57e85d962215273

Published CVSS scores

5.5NIST NVDCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/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.

Daily unique IPsNo honeypot observations are available for this CVE in the selected window.

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-476NULL Pointer Dereference
T1499Endpoint Denial of Service

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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