CVE-2026-80842 (GCVE-0-2026-80842)
Vulnerability from cvelistv5 – Published: 2026-09-04 15:54 – Updated: 2026-10-19 08:44| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
7b54aaaf53cb784411426c64482af0435f7c845e , < 3afaaee2f972aec9059110953adb62fa3cf5c4bd
(git)
Affected: 7b54aaaf53cb784411426c64482af0435f7c845e , < 22226a2c3b90f15b0925f1464470d3baa6c5677e (git) Affected: 7b54aaaf53cb784411426c64482af0435f7c845e , < 7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686 (git) Affected: 7b54aaaf53cb784411426c64482af0435f7c845e , < 3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50 (git) Affected: 7b54aaaf53cb784411426c64482af0435f7c845e , < c069f29da72324697aa4b7cab5b3647a7d24a575 (git) Affected: 7b54aaaf53cb784411426c64482af0435f7c845e , < 3f4752996735e0628af559aa8da1d872c2fac13b (git) Affected: 7b54aaaf53cb784411426c64482af0435f7c845e , < 57f94d3f4dee8b54d63cefddf1112be4656ef9e6 (git) Affected: 7b54aaaf53cb784411426c64482af0435f7c845e , < 50e5c6605cc9c2dd57bd2d1b3459674d19738983 (git) |
guessed | |
| Linux | Linux |
Affected:
5.15
Unaffected: 0 , < 5.15 (semver) Unaffected: 5.15.220 , ≤ 5.15.* (semver) Unaffected: 6.1.187 , ≤ 6.1.* (semver) Unaffected: 6.6.156 , ≤ 6.6.* (semver) Unaffected: 6.12.108 , ≤ 6.12.* (semver) Unaffected: 6.18.49 , ≤ 6.18.* (semver) Unaffected: 7.1.13 , ≤ 7.1.* (semver) Unaffected: 7.2.3 , ≤ 7.2.* (semver) Unaffected: 7.3 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/bridge/br_multicast.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
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},
{
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{
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"versionType": "git"
},
{
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"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/bridge/br_multicast.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"lessThan": "5.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.220",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.187",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.156",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.108",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.49",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.220",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.187",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.156",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.108",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.49",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.13",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.3",
"versionStartIncluding": "5.15",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "5.15",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mcast: fix use-after-free of a master VLAN\u0027s multicast context\n\nbr_multicast_toggle_one_vlan() clears BR_VLFLAG_MCAST_ENABLED under\nbr-\u003emulticast_lock before stopping a VLAN\u0027s multicast context. That is\nthe teardown handshake: lockless readers gate on the flag through\nbr_multicast_ctx_should_use() -\u003e 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-\u003emulticast_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-\u003emulticast_lock,\nso it is not affected.\n\nThe reader is the bridge transmit path. For a master VLAN\nbr_multicast_rcv() selects brmctx = \u0026vlan-\u003ebr_mcast_ctx with\npmctx = NULL, so IGMP sent to the bridge device re-arms the context\u0027s\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-\u003emulticast_lock before\nbr_multicast_ctx_deinit() drains the context."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-19T08:44:35.389Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/3afaaee2f972aec9059110953adb62fa3cf5c4bd"
},
{
"url": "https://git.kernel.org/stable/c/22226a2c3b90f15b0925f1464470d3baa6c5677e"
},
{
"url": "https://git.kernel.org/stable/c/7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686"
},
{
"url": "https://git.kernel.org/stable/c/3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50"
},
{
"url": "https://git.kernel.org/stable/c/c069f29da72324697aa4b7cab5b3647a7d24a575"
},
{
"url": "https://git.kernel.org/stable/c/3f4752996735e0628af559aa8da1d872c2fac13b"
},
{
"url": "https://git.kernel.org/stable/c/57f94d3f4dee8b54d63cefddf1112be4656ef9e6"
},
{
"url": "https://git.kernel.org/stable/c/50e5c6605cc9c2dd57bd2d1b3459674d19738983"
}
],
"title": "net: bridge: mcast: fix use-after-free of a master VLAN\u0027s multicast context",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-80842",
"datePublished": "2026-09-04T15:54:52.459Z",
"dateReserved": "2026-08-26T14:34:25.796Z",
"dateUpdated": "2026-10-19T08:44:35.389Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2026-80842",
"date": "2026-11-10",
"epss": "0.00177",
"percentile": "0.07257"
},
"microsoft_vex": {
"current_release_date": "2026-09-24T01:18:36.000Z",
"cve": "CVE-2026-80842",
"id": "msrc_CVE-2026-80842",
"initial_release_date": "2026-09-06T04:58:46.000Z",
"product_status:fixed": "1",
"product_status:known_affected": "2",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "net: bridge: mcast: fix use-after-free of a master VLAN\u0027s multicast context",
"url": "https://msrc.microsoft.com/csaf/vex/2026/msrc_cve-2026-80842.json",
"version": "5"
},
"nvd": {
"cve": {
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/bridge/br_multicast.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "3afaaee2f972aec9059110953adb62fa3cf5c4bd",
"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
},
{
"lessThan": "22226a2c3b90f15b0925f1464470d3baa6c5677e",
"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
},
{
"lessThan": "7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686",
"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
},
{
"lessThan": "3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50",
"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
},
{
"lessThan": "c069f29da72324697aa4b7cab5b3647a7d24a575",
"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
},
{
"lessThan": "3f4752996735e0628af559aa8da1d872c2fac13b",
"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
"lessThan": "50e5c6605cc9c2dd57bd2d1b3459674d19738983",
"status": "affected",
"version": "7b54aaaf53cb784411426c64482af0435f7c845e",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/bridge/br_multicast.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.15"
},
{
"lessThan": "5.15",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.220",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.187",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.156",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.108",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.49",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: bridge: mcast: fix use-after-free of a master VLAN\u0027s multicast context\n\nbr_multicast_toggle_one_vlan() clears BR_VLFLAG_MCAST_ENABLED under\nbr-\u003emulticast_lock before stopping a VLAN\u0027s multicast context. That is\nthe teardown handshake: lockless readers gate on the flag through\nbr_multicast_ctx_should_use() -\u003e 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-\u003emulticast_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-\u003emulticast_lock,\nso it is not affected.\n\nThe reader is the bridge transmit path. For a master VLAN\nbr_multicast_rcv() selects brmctx = \u0026vlan-\u003ebr_mcast_ctx with\npmctx = NULL, so IGMP sent to the bridge device re-arms the context\u0027s\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-\u003emulticast_lock before\nbr_multicast_ctx_deinit() drains the context."
}
],
"id": "CVE-2026-80842",
"lastModified": "2026-10-19T09:17:19.597",
"metrics": {},
"published": "2026-09-04T16:18:12.727",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/22226a2c3b90f15b0925f1464470d3baa6c5677e"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3a0ad4fcdfa0b7dba1876de14a12cb65c8b5ca50"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3afaaee2f972aec9059110953adb62fa3cf5c4bd"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3f4752996735e0628af559aa8da1d872c2fac13b"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/50e5c6605cc9c2dd57bd2d1b3459674d19738983"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/57f94d3f4dee8b54d63cefddf1112be4656ef9e6"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7c54fd8cfbcf371a5ef50db5c53fe6e85fb76686"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c069f29da72324697aa4b7cab5b3647a7d24a575"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
},
"redhat_vex": {
"aggregate_severity": "Important",
"current_release_date": "2026-11-04T23:35:55+00:00",
"cve": "CVE-2026-80842",
"id": "CVE-2026-80842",
"initial_release_date": "2026-09-04T00:00:00+00:00",
"product_status:known_affected": "161",
"product_status:known_not_affected": "28",
"product_status:under_investigation": "14",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: net: bridge: mcast: fix use-after-free of a master VLAN\u0027s multicast context",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2026/cve-2026-80842.json",
"version": "3"
}
}
}
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
How durations are calculated
Following the VTEM framework (Black Hat USA 2015), time to patch starts when the vendor or a coordinator was informed, total time to patch at discovery, and disclosure to patch at public disclosure; vendor response time runs from the report to its acknowledgement. Time to exploit and time unpatched start at the earliest discovery or report, falling back to public disclosure. Unpatched time ends at the first recorded patch, or the calculation time when no patch is recorded. Exploitation to patch shows the interval between those two events; a published proof of concept is a public exploit, not exploitation.
Each result shows its source dates. A negative interval means the end event came first; when date-only inputs leave the order open, the result says so. Date-only inputs are approximate. The earliest evidence wins: KEV report dates and sightings are labelled as such. Records describing another vulnerability are listed but never calculated from, and a PoC alone does not establish exploitation. Missing patch evidence does not prove that no patch exists. Filters below change the event list only.
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The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.