CVE-2026-90055

Kernel warnings via negative ATM shift counts

Published Sep 17, 2026 · Updated Sep 17, 2026

Invalid shifts in Linux USB ATM support allow local users to trigger kernel warnings by binding an ATM socket to an affected device. usbatm_atm_init() initializes vpi_bits and vci_bits to the -1 sentinel, which __vcc_connect() incorrectly uses as a bit-shift count. The path requires an initialized USB ATM device; the published trace demonstrates UBSAN warnings, not a confirmed crash or privilege escalation.

CVSS severity3.3
Low
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Invalid shifts in Linux USB ATM support allow local users to trigger kernel warnings by binding an ATM socket to an affected device. usbatm_atm_init() initializes vpi_bits and vci_bits to the -1 sentinel, which __vcc_connect() incorrectly uses as a bit-shift count. The path requires an initialized USB ATM device; the published trace demonstrates UBSAN warnings, not a confirmed crash or privilege escalation.

The record

CVE
CVE-2026-90055
Published
Sep 17, 2026
Updated
Sep 17, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
local
Privileges
authenticated

Timeline

How it unfolded

  1. Sep 17, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 17, 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=2.6.13
  2. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422
  3. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <561cbd6d49022c9a383e22a39c87a165a4d39f9c
  4. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <75667703115154a4fd9cf259d4f826d8729cbcda
  5. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <76bc7c3a44856744b64aa91d9afe6d9522a78c42
  6. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <7baa0c92be39eb3da755ed6f200497a57078c47b
  7. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <8442586526c406527bf31206e538c0ce6bc672e6
  8. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <a60fd8c6dbaa76da4163cf225ed2b9e982540f39
  9. Affected versionversion=c59bba75fa500f13ef14215d599ee0d7faa1b954 <ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c

What conditions does exploitation require?

Attack vectorlocal
Required privilegesauthenticated

What is affected?

The Linux Kernel Organization · Linuxversion=2.6.13; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <1e964d414bfd9f8dfe9948d08e4b9dda4ed2e422; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <561cbd6d49022c9a383e22a39c87a165a4d39f9c; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <75667703115154a4fd9cf259d4f826d8729cbcda; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <76bc7c3a44856744b64aa91d9afe6d9522a78c42; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <7baa0c92be39eb3da755ed6f200497a57078c47b; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <8442586526c406527bf31206e538c0ce6bc672e6; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <a60fd8c6dbaa76da4163cf225ed2b9e982540f39; version=c59bba75fa500f13ef14215d599ee0d7faa1b954 <ff7f77a234f7b74e5955a6e34fa74eca4c9ca44c

Published CVSS scores

3.3Amazon LinuxCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:L

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.

Activity data is delayed. The latest report is Sep 28, 2026.

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

No observations available

Sep 22, 2026Sep 28, 2026
Latest reporting daySep 28, 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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