CVE-2026-63903

System crash via short USB status packet

Published Jul 19, 2026 · Updated Jul 19, 2026

Out-of-bounds read in the Linux Kernel belkin_sa USB serial driver allows physically proximate attackers to crash the system. The interrupt callback assumes a four-byte status report and reads LSR and MSR bytes at offsets 2 and 3 without checking the completed transfer's actual length. Exploitation requires connection of a crafted USB serial device while the affected driver is present; the bounded consequence is a host crash.

CVSS severity5.5
Medium
EPSS probability0.22%
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 belkin_sa USB serial driver allows physically proximate attackers to crash the system. The interrupt callback assumes a four-byte status report and reads LSR and MSR bytes at offsets 2 and 3 without checking the completed transfer's actual length. Exploitation requires connection of a crafted USB serial device while the affected driver is present; the bounded consequence is a host crash.

The record

CVE
CVE-2026-63903
Published
Jul 19, 2026
Updated
Jul 19, 2026
Vendor
The Linux Kernel Organization
Product
Linux Kernel
Classifications
CWE-125, T1200
Attack vector
physical
Privileges
unauthenticated

Timeline

How it unfolded

  1. Jul 19, 2026CVE publishedPublication date reported by the CVE source.
  2. Jul 19, 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=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <22823a319fb2afdf02cacafbed8b613b757efbc8
  2. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <37e54d1b986df35c936d81e5b59a7aa3ec6938f0
  3. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4ce058df2ee02cc2a0f0fd5cd64ce6f1482a0b65
  4. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6a4602221cba7a738442328d66a2f0b1c9bf6e17
  5. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <db1e7eb6203d534dad64cac2c793b69e561e657b
  6. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f1617539ab90e67da788959bfd314076f093a11a
  7. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f361359a952da15e70e693c2d7dca5c5843eae3e
  8. Affected versionversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ffb739a49186ea784bbd9cb91b647f062395b419
  9. Affected versionversion=2.6.12

What conditions does exploitation require?

Attack vectorphysical
Required privilegesunauthenticated

What is affected?

The Linux Kernel Organization · Linux Kernelversion=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <22823a319fb2afdf02cacafbed8b613b757efbc8; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <37e54d1b986df35c936d81e5b59a7aa3ec6938f0; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <4ce058df2ee02cc2a0f0fd5cd64ce6f1482a0b65; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <6a4602221cba7a738442328d66a2f0b1c9bf6e17; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <db1e7eb6203d534dad64cac2c793b69e561e657b; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f1617539ab90e67da788959bfd314076f093a11a; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <f361359a952da15e70e693c2d7dca5c5843eae3e; version=1da177e4c3f41524e886b7f1b8a0c1fc7321cac2 <ffb739a49186ea784bbd9cb91b647f062395b419; version=2.6.12

Published CVSS scores

5.5Red HatCVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H
2.4Amazon LinuxCVSS:3.1/AV:P/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

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)
Vectorphysical
Privilegesunauthenticated
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

CWE-125Out-of-bounds Read
T1200Hardware Additions

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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