CVE-2026-98550ModerateNetworkRevised 24 Oct

tipc: reject invalid and unexpected GRP_ACK_MSG to prevent bc_ackers underflow

MSRC advisory NVD CVE.org

Assessment

Severity: Moderate
CVSS base score: 5.3CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Impact: Not stated
EPSS, next 30 days: Not scored yet
Public exploit code: No Nuclei template lists it
Exploitability: Not assessed
Publicly disclosed: No
Customer action: Required: apply the update
Component: Mariner
Weakness: —
Issued by: Linux
Published: 20 Oct 2026 · October 2026
Last revised: 24 Oct 2026Information published.

CVSS 3.1 base metricsRed raises the risk · green lowers it

Attack vector: NetworkAV:N
Attack complexity: LowAC:L
Privileges required: NonePR:N
User interaction: NoneUI:N
Scope: UnchangedS:U
Confidentiality: NoneC:N
Integrity: NoneI:N
Availability: LowA:L

Updates that fix it

0 KBs

No KB listed

MSRC lists no downloadable update, which usually means a service-side fix or a release-notes update. Check the MSRC advisory.

Affected products

1 affected product

azl3 kernel 6.6.157.1-1 on Azure Linux 3.0

What changed

First observed 20 Oct 2026

25 Oct 2026 · 07:41:18 UTC Last revised21 Oct 2026 18:39 UTC → 24 Oct 2026 14:48 UTC
23 Oct 2026 · 09:33:49 UTC Public exploit codeUnknown: exploit-code evidence is incomplete or retained → No Nuclei template listed
23 Oct 2026 · 09:33:49 UTC CISA KEVUnknown: catalog evidence is incomplete or retained → Not listed in the collected catalog
23 Oct 2026 · 09:33:49 UTC Source coverage: public-exploit-codeIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: first-epssIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: cisa-kevIncomplete → Current
23 Oct 2026 · 09:33:49 UTC Source coverage: msrc-cvrfIncomplete → Current
23 Oct 2026 · 08:31:50 UTC Public exploit codeNo Nuclei template listed → Unknown: exploit-code evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC CISA KEVNot listed in the collected catalog → Unknown: catalog evidence is incomplete or retained
23 Oct 2026 · 08:31:50 UTC Source coverage: public-exploit-codeCurrent → Incomplete
23 Oct 2026 · 08:31:50 UTC Source coverage: first-epssCurrent → Incomplete
23 Oct 2026 · 08:31:50 UTC Source coverage: cisa-kevCurrent → Incomplete

Show 2 more recent changes

23 Oct 2026 · 08:31:50 UTCSource coverage: msrc-cvrf Current → Incomplete
21 Oct 2026 · 20:45:25 UTCLast revised 20 Oct 2026 01:11 UTC → 21 Oct 2026 18:39 UTC

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Explore global source statements, affected packages and advisory history for CVE-2026-98550. The catalog has a separate collection scope from Microsoft release records.

cve-program · CVE-2026-98550

Published

Linux

Vendor product

Original vendor version evidence · not evaluated as a NuGet range

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "unaffected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/tipc/group.c"
                    ],
                    "versions": [
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "edc6593c442278fceff0120e8cc58bc592168c35",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "9b94a90651e1fa573c6ac6a5a6b269d5874df2c0",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "507a27435b2bb1f22e3a3674f6a6553eb815021b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "80a9ccfc24d3776ef6753a57315e726475fac7d7",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "478fb08d0c2a53002a721d22b8d6681ec971d90f",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "12cc3a1eac5a2a06b67a7b85f0f48ff241a94d1b",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "b0e517961f09b9f60d338d1ea4e17aacdbf206f0",
                            "status": "affected",
                            "versionType": "git"
                        },
                        {
                            "version": "2f487712b89376fce267223bbb0db93d393d4b09",
                            "lessThan": "99cc2a62e07a44a22254d7beca9ef1f8ad886d0d",
                            "status": "affected",
                            "versionType": "git"
                        }
                    ]
                }

Linux

Vendor product

Original vendor version evidence · not evaluated as a NuGet range

{
                    "product": "Linux",
                    "vendor": "Linux",
                    "defaultStatus": "affected",
                    "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
                    "programFiles": [
                        "net/tipc/group.c"
                    ],
                    "versions": [
                        {
                            "version": "4.15",
                            "status": "affected"
                        },
                        {
                            "version": "0",
                            "lessThan": "4.15",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.10.271",
                            "lessThanOrEqual": "5.10.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "5.15.222",
                            "lessThanOrEqual": "5.15.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.1.189",
                            "lessThanOrEqual": "6.1.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.6.158",
                            "lessThanOrEqual": "6.6.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.12.112",
                            "lessThanOrEqual": "6.12.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "6.18.55",
                            "lessThanOrEqual": "6.18.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.2.9",
                            "lessThanOrEqual": "7.2.*",
                            "status": "unaffected",
                            "versionType": "semver"
                        },
                        {
                            "version": "7.3",
                            "lessThanOrEqual": "*",
                            "status": "unaffected",
                            "versionType": "original_commit_for_fix"
                        }
                    ]
                }