CVE-2026-98550: Software Security Vulnerability Vulnerability

UNKNOWN
Advisory Identifier: GHSA-xqp5-j42w-5fq8
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Advisory Summary

CVE-2026-98550 is a security vulnerability vulnerability (General Security Weakness) affecting Software libraries in the Maven ecosystem. Remediation is available in the latest vendor maintenance releases.

CVE-2026-98550 at a Glance

CVE Identifier CVE-2026-98550
GHSA Identifier GHSA-xqp5-j42w-5fq8
Severity N/A
CVSS v3.1 Base Score N/A
CWE Classification General Security Weakness
Affected Product Software
Package Ecosystem Maven
Published Date
Last Updated

How to Fix CVE-2026-98550

To remediate this vulnerability, upgrade all affected Software dependencies to a patched release. Both direct and transitive dependencies should be checked, as frameworks or security libraries may pull in vulnerable versions transitively.

Verify Direct and Transitive Dependencies

Run the following command in your project directory to verify that all resolved dependencies use the patched release: 

mvn dependency:tree

How to Check if You Are Affected

To determine whether your Java application is affected by CVE-2026-98550, inspect your build dependencies using the Maven Dependency Plugin:

mvn dependency:tree

Analyze the terminal output to locate any version of Software in your dependency tree. If any resolved version matches the vulnerable ranges listed in the table below (for example, versions earlier than the patched release), your application is affected.

Note: The mvn dependency:tree command inspects the resolved dependency graph declared in your project's POM files; it does not perform automated security scanning or inspect runtime dynamic classpaths. Always verify runtime container classpaths and shaded JARs.

Technical Details

Vulnerability Mechanism & Technical Analysis

This vulnerability is classified under General Security Weakness. In Software, software state validation or input boundaries are circumvented during processing. Review the official source advisory statement below for specific affected components, classes, and reproduction details.

Source Advisory Statement

In the Linux kernel, the following vulnerability has been resolved: tipc: reject invalid and unexpected GRP_ACK_MSG to prevent bc_ackers underflow Commit 48a5fe38772b ("tipc: fix bc_ackers underflow on duplicate GRP_ACK_MSG") rejected duplicate/stale ACKs in tipc_group_proto_rcv() by returning early when less_eq(acked, m->bc_acked). However, that check remains incomplete in two ways: 1. When grp->bc_ackers is zero (e.g. on a quiet group, when replicast ACKs were not requested, or after all expected members have already acknowledged), an unexpected GRP_ACK_MSG with acked > m->bc_acked passes less_eq() and unconditionally decrements grp->bc_ackers. Because bc_ackers is a u16, this wraps to 65535, causing tipc_group_bc_cong() to permanently report congestion and blocking all future group broadcasts on the socket. 2. During an active broadcast round (grp->bc_ackers > 0), the sender transmits packet S and advances grp->bc_snd_nxt to S + 1. Receivers increment their expected counter to S + 1 upon consuming packet S, so the only valid ACK value for the current round is strictly acked == grp->bc_snd_nxt. However, tipc_group_update_bc_members() initializes each member's m->bc_acked to prev = grp->bc_snd_nxt - 1 (S - 1 before increment). This leaves a 2-sequence gap (S - 1 to S + 1) in sequence space. An incoming ACK is therefore neither rejected as duplicate nor prevented from decrementing grp->bc_ackers if an unexpected or stale value (such as S) is received. A member sending acked = S followed by acked = S + 1 could decrement grp->bc_ackers twice in the same round, prematurely clearing bc_ackers or underflowing it. Fix this by: - Dropping GRP_ACK_MSG immediately if grp->bc_ackers is zero. - Requiring acked == grp->bc_snd_nxt and rejecting duplicates where m->bc_acked == acked. Because replicast broadcast rounds are strictly sequential, only grp->bc_snd_nxt can be acknowledged, and each member can acknowledge at most once per round. Note that a related pre-existing issue in tipc_group_delete_member() (where grp->bc_ackers decrementing to zero upon member departure does not restore *grp->open or trigger a socket wakeup) will be addressed in a separate patch.

References

NVD — CVE-2026-98550 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-98550
git.kernel.org/stable/c/12cc3a1eac... WEB
https://git.kernel.org/stable/c/12cc3a1eac5a2a06b67a7b85f0f48ff241a94d1b
git.kernel.org/stable/c/478fb08d0c... WEB
https://git.kernel.org/stable/c/478fb08d0c2a53002a721d22b8d6681ec971d90f
git.kernel.org/stable/c/507a27435b... WEB
https://git.kernel.org/stable/c/507a27435b2bb1f22e3a3674f6a6553eb815021b
git.kernel.org/stable/c/80a9ccfc24... WEB
https://git.kernel.org/stable/c/80a9ccfc24d3776ef6753a57315e726475fac7d7
git.kernel.org/stable/c/99cc2a62e0... WEB
https://git.kernel.org/stable/c/99cc2a62e07a44a22254d7beca9ef1f8ad886d0d
git.kernel.org/stable/c/9b94a90651... WEB
https://git.kernel.org/stable/c/9b94a90651e1fa573c6ac6a5a6b269d5874df2c0
git.kernel.org/stable/c/b0e517961f... WEB
https://git.kernel.org/stable/c/b0e517961f09b9f60d338d1ea4e17aacdbf206f0
git.kernel.org/stable/c/edc6593c44... WEB
https://git.kernel.org/stable/c/edc6593c442278fceff0120e8cc58bc592168c35

Frequently Asked Questions

What is CVE-2026-98550?
CVE-2026-98550 is a security vulnerability in Software classified as a security vulnerability vulnerability under General Security Weakness.
Which Software versions are affected?
Affected versions include releases prior to current release patches.
What version fixes CVE-2026-98550?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-98550?
CVE-2026-98550 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2026-98550?
Run the dependency tree command: 'mvn dependency:tree'. This command lists direct and transitive dependencies in your build configuration so you can verify if a vulnerable version is resolved.
Machine-readable OSV JSON OSV v1.5 Schema
Normalized schema output
View Raw JSON 
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  "schema_version" : "1.4.0",
  "id" : "GHSA-xqp5-j42w-5fq8",
  "modified" : "2026-10-18T18:31:53Z",
  "published" : "2026-10-18T18:31:53Z",
  "aliases" : [ "CVE-2026-98550" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\ntipc: reject invalid and unexpected GRP_ACK_MSG to prevent bc_ackers underflow\n\nCommit 48a5fe38772b (\"tipc: fix bc_ackers underflow on duplicate\nGRP_ACK_MSG\") rejected duplicate/stale ACKs in tipc_group_proto_rcv()\nby returning early when less_eq(acked, m->bc_acked).\n\nHowever, that check remains incomplete in two ways:\n\n1. When grp->bc_ackers is zero (e.g. on a quiet group, when replicast\n   ACKs were not requested, or after all expected members have already\n   acknowledged), an unexpected GRP_ACK_MSG with acked > m->bc_acked\n   passes less_eq() and unconditionally decrements grp->bc_ackers.\n   Because bc_ackers is a u16, this wraps to 65535, causing\n   tipc_group_bc_cong() to permanently report congestion and blocking\n   all future group broadcasts on the socket.\n\n2. During an active broadcast round (grp->bc_ackers > 0), the sender\n   transmits packet S and advances grp->bc_snd_nxt to S + 1. Receivers\n   increment their expected counter to S + 1 upon consuming packet S,\n   so the only valid ACK value for the current round is strictly\n   acked == grp->bc_snd_nxt.\n\n   However, tipc_group_update_bc_members() initializes each member's\n   m->bc_acked to prev = grp->bc_snd_nxt - 1 (S - 1 before increment).\n   This leaves a 2-sequence gap (S - 1 to S + 1) in sequence space.\n   An incoming ACK is therefore neither rejected as duplicate nor\n   prevented from decrementing grp->bc_ackers if an unexpected or stale\n   value (such as S) is received. A member sending acked = S followed\n   by acked = S + 1 could decrement grp->bc_ackers twice in the same\n   round, prematurely clearing bc_ackers or underflowing it.\n\nFix this by:\n- Dropping GRP_ACK_MSG immediately if grp->bc_ackers is zero.\n- Requiring acked == grp->bc_snd_nxt and rejecting duplicates where\n  m->bc_acked == acked. Because replicast broadcast rounds are strictly\n  sequential, only grp->bc_snd_nxt can be acknowledged, and each member\n  can acknowledge at most once per round.\n\nNote that a related pre-existing issue in tipc_group_delete_member()\n(where grp->bc_ackers decrementing to zero upon member departure does\nnot restore *grp->open or trigger a socket wakeup) will be addressed\nin a separate patch.",
  "severity" : [ ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-98550"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/12cc3a1eac5a2a06b67a7b85f0f48ff241a94d1b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/478fb08d0c2a53002a721d22b8d6681ec971d90f"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/507a27435b2bb1f22e3a3674f6a6553eb815021b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/80a9ccfc24d3776ef6753a57315e726475fac7d7"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/99cc2a62e07a44a22254d7beca9ef1f8ad886d0d"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/9b94a90651e1fa573c6ac6a5a6b269d5874df2c0"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/b0e517961f09b9f60d338d1ea4e17aacdbf206f0"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/edc6593c442278fceff0120e8cc58bc592168c35"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : null,
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-10-18T16:17:07Z"
  }
}