{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2025-21920", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-12-29T08:45:45.788Z", "datePublished": "2025-04-01T15:40:54.595Z", "dateUpdated": "2026-05-11T21:09:05.513Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-11T21:09:05.513Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nvlan: enforce underlying device type\n\nCurrently, VLAN devices can be created on top of non-ethernet devices.\n\nBesides the fact that it doesn't make much sense, this also causes a\nbug which leaks the address of a kernel function to usermode.\n\nWhen creating a VLAN device, we initialize GARP (garp_init_applicant)\nand MRP (mrp_init_applicant) for the underlying device.\n\nAs part of the initialization process, we add the multicast address of\neach applicant to the underlying device, by calling dev_mc_add.\n\n__dev_mc_add uses dev->addr_len to determine the length of the new\nmulticast address.\n\nThis causes an out-of-bounds read if dev->addr_len is greater than 6,\nsince the multicast addresses provided by GARP and MRP are only 6\nbytes long.\n\nThis behaviour can be reproduced using the following commands:\n\nip tunnel add gretest mode ip6gre local ::1 remote ::2 dev lo\nip l set up dev gretest\nip link add link gretest name vlantest type vlan id 100\n\nThen, the following command will display the address of garp_pdu_rcv:\n\nip maddr show | grep 01:80:c2:00:00:21\n\nFix the bug by enforcing the type of the underlying device during VLAN\ndevice initialization." } ], "affected": [ { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/8021q/vlan.c" ], "versions": [ { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "7f1564b2b2072b7aa1ac75350e9560a07c7a44fd", "status": "affected", "versionType": "git" }, { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "fa40ebef69234e39ec2d26930d045f2fb9a8cb2b", "status": "affected", "versionType": "git" }, { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "0fb7aa04c19eac4417f360a9f7611a60637bdacc", "status": "affected", "versionType": "git" }, { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "5a515d13e15536e82c5c7c83eb6cf5bc4827fee5", "status": "affected", "versionType": "git" }, { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "3561442599804905c3defca241787cd4546e99a7", "status": "affected", "versionType": "git" }, { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "30e8aee77899173a82ae5ed89f536c096f20aaeb", "status": "affected", "versionType": "git" }, { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "b6c72479748b7ea09f53ed64b223cee6463dc278", "status": "affected", "versionType": "git" }, { "version": "22bedad3ce112d5ca1eaf043d4990fa2ed698c87", "lessThan": "b33a534610067ade2bdaf2052900aaad99701353", "status": "affected", "versionType": "git" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/8021q/vlan.c" ], "versions": [ { "version": "2.6.35", "status": "affected" }, { "version": "0", "lessThan": "2.6.35", "status": "unaffected", "versionType": "semver" }, { "version": "5.4.291", "lessThanOrEqual": "5.4.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.10.235", "lessThanOrEqual": "5.10.*", "status": "unaffected", "versionType": "semver" }, { "version": "5.15.179", "lessThanOrEqual": "5.15.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.1.131", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.6.83", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.12.19", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.13.7", "lessThanOrEqual": "6.13.*", "status": "unaffected", "versionType": "semver" }, { "version": "6.14", "lessThanOrEqual": "*", "status": "unaffected", "versionType": "original_commit_for_fix" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.4.291" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.10.235" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "5.15.179" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.1.131" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.6.83" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.12.19" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.13.7" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "2.6.35", "versionEndExcluding": "6.14" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/7f1564b2b2072b7aa1ac75350e9560a07c7a44fd" }, { "url": "https://git.kernel.org/stable/c/fa40ebef69234e39ec2d26930d045f2fb9a8cb2b" }, { "url": "https://git.kernel.org/stable/c/0fb7aa04c19eac4417f360a9f7611a60637bdacc" }, { "url": "https://git.kernel.org/stable/c/5a515d13e15536e82c5c7c83eb6cf5bc4827fee5" }, { "url": "https://git.kernel.org/stable/c/3561442599804905c3defca241787cd4546e99a7" }, { "url": "https://git.kernel.org/stable/c/30e8aee77899173a82ae5ed89f536c096f20aaeb" }, { "url": "https://git.kernel.org/stable/c/b6c72479748b7ea09f53ed64b223cee6463dc278" }, { "url": "https://git.kernel.org/stable/c/b33a534610067ade2bdaf2052900aaad99701353" } ], "title": "vlan: enforce underlying device type", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 7.1, "attackVector": "LOCAL", "baseSeverity": "HIGH", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:N/A:H", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "HIGH", "privilegesRequired": "LOW", "confidentialityImpact": "HIGH" } }, { "other": { "type": "ssvc", "content": { "id": "CVE-2025-21920", "role": "CISA Coordinator", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "version": "2.0.3", "timestamp": "2025-10-01T20:07:55.880454Z" } } } ], "problemTypes": [ { "descriptions": [ { "lang": "en", "type": "CWE", "cweId": "CWE-125", "description": "CWE-125 Out-of-bounds Read" } ] } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2025-10-01T20:17:03.075Z" } }, { "title": "CVE Program Container", "references": [ { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00045.html" }, { "url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html" } ], "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2025-11-03T19:39:13.839Z" } } ] } }