CVE-2026-80842: Software Security Vulnerability Vulnerability

UNKNOWN
Advisory Identifier: GHSA-4rr3-fvjp-hj2g
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Advisory Summary

CVE-2026-80842 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-2026-80842 at a Glance

CVE Identifier CVE-2026-80842
GHSA Identifier GHSA-4rr3-fvjp-hj2g
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-2026-80842

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-2026-80842, 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: net: bridge: mcast: fix use-after-free of a master VLAN's multicast context br_multicast_toggle_one_vlan() clears BR_VLFLAG_MCAST_ENABLED under br->multicast_lock before stopping a VLAN's multicast context. That is the teardown handshake: lockless readers gate on the flag through br_multicast_ctx_should_use() -> br_multicast_ctx_vlan_disabled(), so once it is cleared under the lock no reader can arm the context again. For a master VLAN the handshake never runs. __vlan_del() clears BRIDGE_VLAN_INFO_BRENTRY before calling br_vlan_put_master(), so br_multicast_toggle_one_vlan(masterv, false) returns early on !br_vlan_is_brentry(vlan): the flag stays set and br->multicast_lock is never taken. br_vlan_put_master() then drains the context in br_multicast_ctx_deinit() and frees the VLAN through call_rcu(), while a reader still inside rcu_read_lock() sees the context as enabled and re-arms it. The port and port-VLAN branch of the function has no br_vlan_is_brentry() test and flips the flag under br->multicast_lock, so it is not affected. The reader is the bridge transmit path. For a master VLAN br_multicast_rcv() selects brmctx = &vlan->br_mcast_ctx with pmctx = NULL, so IGMP sent to the bridge device re-arms the context's timers after br_multicast_ctx_deinit() has already stopped them. BUG: KASAN: slab-use-after-free in detach_if_pending+0x412/0x4a0 Write of size 8 at addr ffff88810ac39918 by task brmc/601 __mod_timer+0x51a/0xc50 br_multicast_host_join+0x25b/0x390 __br_multicast_add_group+0x468/0x530 br_ip4_multicast_add_group+0x1a0/0x260 br_multicast_rcv+0x2cda/0x61e0 br_dev_xmit+0x6c4/0x1540 Allocated by task 610: br_vlan_add+0x111/0xb40 br_vlan_info+0x370/0x3e0 Freed by task 0: kfree+0x1a7/0x4f0 rcu_core+0x7dc/0x10a0 Only test br_vlan_is_brentry() when enabling, like the br_multicast_ctx_vlan_global_disabled() test next to it. Disabling then always clears BR_VLFLAG_MCAST_ENABLED under br->multicast_lock before br_multicast_ctx_deinit() drains the context.

References

NVD — CVE-2026-80842 NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-80842
git.kernel.org/stable/c/22226a2c3b... WEB
https://git.kernel.org/stable/c/22226a2c3b90f15b0925f1464470d3baa6c5677e
git.kernel.org/stable/c/3a0ad4fcdf... WEB
https://git.kernel.org/stable/c/3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50
git.kernel.org/stable/c/3afaaee2f9... WEB
https://git.kernel.org/stable/c/3afaaee2f972aec9059110953adb62fa3cf5c4bd
git.kernel.org/stable/c/3f47529967... WEB
https://git.kernel.org/stable/c/3f4752996735e0628af559aa8da1d872c2fac13b
git.kernel.org/stable/c/50e5c6605c... WEB
https://git.kernel.org/stable/c/50e5c6605cc9c2dd57bd2d1b3459674d19738983
git.kernel.org/stable/c/57f94d3f4d... WEB
https://git.kernel.org/stable/c/57f94d3f4dee8b54d63cefddf1112be4656ef9e6
git.kernel.org/stable/c/7c54fd8cfb... WEB
https://git.kernel.org/stable/c/7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686
git.kernel.org/stable/c/c069f29da7... WEB
https://git.kernel.org/stable/c/c069f29da72324697aa4b7cab5b3647a7d24a575

Frequently Asked Questions

What is CVE-2026-80842?
CVE-2026-80842 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-2026-80842?
Upgrading to current release patches (or the latest patched release for your respective branch) resolves the vulnerability.
What CWE is associated with CVE-2026-80842?
CVE-2026-80842 is classified under General Security Weakness.
How can I check Maven dependencies for CVE-2026-80842?
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 
{
  "schema_version" : "1.4.0",
  "id" : "GHSA-4rr3-fvjp-hj2g",
  "modified" : "2026-09-04T18:31:28Z",
  "published" : "2026-09-04T18:31:28Z",
  "aliases" : [ "CVE-2026-80842" ],
  "details" : "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mcast: fix use-after-free of a master VLAN's multicast context\n\nbr_multicast_toggle_one_vlan() clears BR_VLFLAG_MCAST_ENABLED under\nbr->multicast_lock before stopping a VLAN's multicast context.  That is\nthe teardown handshake: lockless readers gate on the flag through\nbr_multicast_ctx_should_use() -> br_multicast_ctx_vlan_disabled(), so\nonce it is cleared under the lock no reader can arm the context again.\n\nFor a master VLAN the handshake never runs.  __vlan_del() clears\nBRIDGE_VLAN_INFO_BRENTRY before calling br_vlan_put_master(), so\nbr_multicast_toggle_one_vlan(masterv, false) returns early on\n!br_vlan_is_brentry(vlan): the flag stays set and br->multicast_lock is\nnever taken.  br_vlan_put_master() then drains the context in\nbr_multicast_ctx_deinit() and frees the VLAN through call_rcu(), while a\nreader still inside rcu_read_lock() sees the context as enabled and\nre-arms it.  The port and port-VLAN branch of the function has no\nbr_vlan_is_brentry() test and flips the flag under br->multicast_lock,\nso it is not affected.\n\nThe reader is the bridge transmit path.  For a master VLAN\nbr_multicast_rcv() selects brmctx = &vlan->br_mcast_ctx with\npmctx = NULL, so IGMP sent to the bridge device re-arms the context's\ntimers after br_multicast_ctx_deinit() has already stopped them.\n\n  BUG: KASAN: slab-use-after-free in detach_if_pending+0x412/0x4a0\n  Write of size 8 at addr ffff88810ac39918 by task brmc/601\n   __mod_timer+0x51a/0xc50\n   br_multicast_host_join+0x25b/0x390\n   __br_multicast_add_group+0x468/0x530\n   br_ip4_multicast_add_group+0x1a0/0x260\n   br_multicast_rcv+0x2cda/0x61e0\n   br_dev_xmit+0x6c4/0x1540\n  Allocated by task 610:\n   br_vlan_add+0x111/0xb40\n   br_vlan_info+0x370/0x3e0\n  Freed by task 0:\n   kfree+0x1a7/0x4f0\n   rcu_core+0x7dc/0x10a0\n\nOnly test br_vlan_is_brentry() when enabling, like the\nbr_multicast_ctx_vlan_global_disabled() test next to it.  Disabling then\nalways clears BR_VLFLAG_MCAST_ENABLED under br->multicast_lock before\nbr_multicast_ctx_deinit() drains the context.",
  "severity" : [ ],
  "affected" : [ ],
  "references" : [ {
    "type" : "ADVISORY",
    "url" : "https://nvd.nist.gov/vuln/detail/CVE-2026-80842"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/22226a2c3b90f15b0925f1464470d3baa6c5677e"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/3afaaee2f972aec9059110953adb62fa3cf5c4bd"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/3f4752996735e0628af559aa8da1d872c2fac13b"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/50e5c6605cc9c2dd57bd2d1b3459674d19738983"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/57f94d3f4dee8b54d63cefddf1112be4656ef9e6"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686"
  }, {
    "type" : "WEB",
    "url" : "https://git.kernel.org/stable/c/c069f29da72324697aa4b7cab5b3647a7d24a575"
  } ],
  "database_specific" : {
    "cwe_ids" : [ ],
    "severity" : null,
    "github_reviewed" : false,
    "github_reviewed_at" : null,
    "nvd_published_at" : "2026-09-04T16:18:12Z"
  }
}