CVE-2026-80842

Kernel memory corruption via master VLAN teardown race

Published Sep 4, 2026 · Updated Sep 4, 2026

Use-after-free in Linux kernel bridge multicast handling allows attackers to corrupt kernel memory via unspecified vectors. During master VLAN deletion, br_multicast_toggle_one_vlan() returns before clearing BR_VLFLAG_MCAST_ENABLED, so the transmit path can re-arm timers after br_multicast_ctx_deinit() frees the context. Reaching the flaw requires master VLAN teardown to race with IGMP sent to the bridge device; port and port-VLAN contexts are not affected.

CVSS severityUnavailable
Unscored
EPSS probability0.18%
Next 30 days · Sep 16, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkNot available
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Summary

What happened

Use-after-free in Linux kernel bridge multicast handling allows attackers to corrupt kernel memory via unspecified vectors. During master VLAN deletion, br_multicast_toggle_one_vlan() returns before clearing BR_VLFLAG_MCAST_ENABLED, so the transmit path can re-arm timers after br_multicast_ctx_deinit() frees the context. Reaching the flaw requires master VLAN teardown to race with IGMP sent to the bridge device; port and port-VLAN contexts are not affected.

The record

CVE
CVE-2026-80842
Published
Sep 4, 2026
Updated
Sep 4, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
Unavailable
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Sep 4, 2026CVE publishedPublication date reported by the CVE source.
  2. Sep 4, 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=5.15
  2. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <22226a2c3b90f15b0925f1464470d3baa6c5677e
  3. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50
  4. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <3afaaee2f972aec9059110953adb62fa3cf5c4bd
  5. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <3f4752996735e0628af559aa8da1d872c2fac13b
  6. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <50e5c6605cc9c2dd57bd2d1b3459674d19738983
  7. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <57f94d3f4dee8b54d63cefddf1112be4656ef9e6
  8. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686
  9. Affected versionversion=7b54aaaf53cb784411426c64482af0435f7c845e <c069f29da72324697aa4b7cab5b3647a7d24a575

What conditions does exploitation require?

Attack vectorUnavailable in this record.
Required privilegesUnavailable in this record.

What is affected?

The Linux Kernel Organization · Linuxversion=5.15; version=7b54aaaf53cb784411426c64482af0435f7c845e <22226a2c3b90f15b0925f1464470d3baa6c5677e; version=7b54aaaf53cb784411426c64482af0435f7c845e <3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50; version=7b54aaaf53cb784411426c64482af0435f7c845e <3afaaee2f972aec9059110953adb62fa3cf5c4bd; version=7b54aaaf53cb784411426c64482af0435f7c845e <3f4752996735e0628af559aa8da1d872c2fac13b; version=7b54aaaf53cb784411426c64482af0435f7c845e <50e5c6605cc9c2dd57bd2d1b3459674d19738983; version=7b54aaaf53cb784411426c64482af0435f7c845e <57f94d3f4dee8b54d63cefddf1112be4656ef9e6; version=7b54aaaf53cb784411426c64482af0435f7c845e <7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686; version=7b54aaaf53cb784411426c64482af0435f7c845e <c069f29da72324697aa4b7cab5b3647a7d24a575

Published CVSS scores

No CVSS assessment is available in this record.

CVSS describes severity. EPSS estimates exploitation probability.

Attacks

What attackers are doing with it

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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)
VectorUnavailable
PrivilegesUnavailable
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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