CVE-2026-98550Hinoki check available

Broadcast hang via unchecked TIPC acknowledgment accounting

Published Oct 18, 2026 · Updated Oct 18, 2026

ACK validation failure in Linux 4.15 TIPC allows attackers to hang group broadcasts through crafted acknowledgment messages. The tipc_group_proto_rcv() handler accepts unexpected GRP_ACK_MSG values and decrements the unsigned bc_ackers counter without verifying that an acknowledgment is outstanding for the current round. Triggering requires messages associated with a recognized group member; counter underflow permanently blocks subsequent broadcasts on the affected socket, rather than crashing the kernel.

CVSS severityUnavailable
Unscored
EPSS probability0.21%
Next 30 days · Oct 19, 2026
Known exploitationUnconfirmed
Based on sourced intelligence
Hinoki checkAvailable
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Summary

What happened

ACK validation failure in Linux 4.15 TIPC allows attackers to hang group broadcasts through crafted acknowledgment messages. The tipc_group_proto_rcv() handler accepts unexpected GRP_ACK_MSG values and decrements the unsigned bc_ackers counter without verifying that an acknowledgment is outstanding for the current round. Triggering requires messages associated with a recognized group member; counter underflow permanently blocks subsequent broadcasts on the affected socket, rather than crashing the kernel.

The record

CVE
CVE-2026-98550
Published
Oct 18, 2026
Updated
Oct 18, 2026
Vendor
The Linux Kernel Organization
Product
Linux
Classifications
T1499.004
Attack vector
Unavailable
Privileges
Unavailable

Timeline

How it unfolded

  1. Oct 18, 2026CVE publishedPublication date reported by the CVE source.
  2. Oct 18, 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?

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  1. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <12cc3a1eac5a2a06b67a7b85f0f48ff241a94d1b
  2. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <478fb08d0c2a53002a721d22b8d6681ec971d90f
  3. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <507a27435b2bb1f22e3a3674f6a6553eb815021b
  4. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <80a9ccfc24d3776ef6753a57315e726475fac7d7
  5. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <99cc2a62e07a44a22254d7beca9ef1f8ad886d0d
  6. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <9b94a90651e1fa573c6ac6a5a6b269d5874df2c0
  7. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <b0e517961f09b9f60d338d1ea4e17aacdbf206f0
  8. Affected versionversion=2f487712b89376fce267223bbb0db93d393d4b09 <edc6593c442278fceff0120e8cc58bc592168c35
  9. Affected versionversion=4.15

What conditions does exploitation require?

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

What is affected?

The Linux Kernel Organization · Linuxversion=2f487712b89376fce267223bbb0db93d393d4b09 <12cc3a1eac5a2a06b67a7b85f0f48ff241a94d1b; version=2f487712b89376fce267223bbb0db93d393d4b09 <478fb08d0c2a53002a721d22b8d6681ec971d90f; version=2f487712b89376fce267223bbb0db93d393d4b09 <507a27435b2bb1f22e3a3674f6a6553eb815021b; version=2f487712b89376fce267223bbb0db93d393d4b09 <80a9ccfc24d3776ef6753a57315e726475fac7d7; version=2f487712b89376fce267223bbb0db93d393d4b09 <99cc2a62e07a44a22254d7beca9ef1f8ad886d0d; version=2f487712b89376fce267223bbb0db93d393d4b09 <9b94a90651e1fa573c6ac6a5a6b269d5874df2c0; version=2f487712b89376fce267223bbb0db93d393d4b09 <b0e517961f09b9f60d338d1ea4e17aacdbf206f0; version=2f487712b89376fce267223bbb0db93d393d4b09 <edc6593c442278fceff0120e8cc58bc592168c35; version=4.15

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

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)
VectorUnavailable
PrivilegesUnavailable
Known exploitationUnconfirmed
Public exploitUnconfirmed

Weakness, pattern, technique

T1499.004Application or System Exploitation

Public exploit references

No public exploit references are available in this record.

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Technologies

Your stack

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