{ "dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": { "cveId": "CVE-2021-47555", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2024-05-24T15:02:54.833Z", "datePublished": "2024-05-24T15:09:57.302Z", "dateUpdated": "2026-05-23T15:20:14.679Z" }, "containers": { "cna": { "providerMetadata": { "orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-05-23T15:20:14.679Z" }, "descriptions": [ { "lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: vlan: fix underflow for the real_dev refcnt\n\nInject error before dev_hold(real_dev) in register_vlan_dev(),\nand execute the following testcase:\n\nip link add dev dummy1 type dummy\nip link add name dummy1.100 link dummy1 type vlan id 100\nip link del dev dummy1\n\nWhen the dummy netdevice is removed, we will get a WARNING as following:\n\n=======================================================================\nrefcount_t: decrement hit 0; leaking memory.\nWARNING: CPU: 2 PID: 0 at lib/refcount.c:31 refcount_warn_saturate+0xbf/0x1e0\n\nand an endless loop of:\n\n=======================================================================\nunregister_netdevice: waiting for dummy1 to become free. Usage count = -1073741824\n\nThat is because dev_put(real_dev) in vlan_dev_free() be called without\ndev_hold(real_dev) in register_vlan_dev(). It makes the refcnt of real_dev\nunderflow.\n\nMove the dev_hold(real_dev) to vlan_dev_init() which is the call-back of\nndo_init(). That makes dev_hold() and dev_put() for vlan's real_dev\nsymmetrical." } ], "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", "net/8021q/vlan_dev.c" ], "versions": [ { "version": "700602b662d7eaa816b1a3cb0abe7a85de358fd4", "lessThan": "5e44178864b38dd70b877985abd7d86fdb95f27d", "status": "affected", "versionType": "git" }, { "version": "e04a7a84bb77f9cdf4475340fe931389bc72331c", "lessThan": "6e800ee43218a56acc93676bbb3d93b74779e555", "status": "affected", "versionType": "git" }, { "version": "21032425c36ff85f16e72ca92193a8c401e4acd5", "lessThan": "f7fc72a508cf115c273a7a29350069def1041890", "status": "affected", "versionType": "git" }, { "version": "563bcbae3ba233c275c244bfce2efe12938f5363", "lessThan": "01d9cc2dea3fde3bad6d27f464eff463496e2b00", "status": "affected", "versionType": "git" }, { "version": "fca96b3f852a1b369b7b2844ce357cd689879934", "status": "affected", "versionType": "git" }, { "version": "5.14.19", "lessThan": "5.15", "status": "affected", "versionType": "semver" } ] }, { "product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": [ "net/8021q/vlan.c", "net/8021q/vlan_dev.c" ], "versions": [ { "version": "5.4.160", "lessThan": "5.4.163", "status": "affected", "versionType": "semver" }, { "version": "5.10.80", "lessThan": "5.10.83", "status": "affected", "versionType": "semver" }, { "version": "5.15.3", "lessThan": "5.15.6", "status": "affected", "versionType": "semver" } ] } ], "cpeApplicability": [ { "nodes": [ { "operator": "OR", "negate": false, "cpeMatch": [ { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.4.160", "versionEndExcluding": "5.4.163" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.10.80", "versionEndExcluding": "5.10.83" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.15.3", "versionEndExcluding": "5.15.6" }, { "vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.14.19" } ] } ] } ], "references": [ { "url": "https://git.kernel.org/stable/c/5e44178864b38dd70b877985abd7d86fdb95f27d" }, { "url": "https://git.kernel.org/stable/c/6e800ee43218a56acc93676bbb3d93b74779e555" }, { "url": "https://git.kernel.org/stable/c/f7fc72a508cf115c273a7a29350069def1041890" }, { "url": "https://git.kernel.org/stable/c/01d9cc2dea3fde3bad6d27f464eff463496e2b00" } ], "title": "net: vlan: fix underflow for the real_dev refcnt", "x_generator": { "engine": "bippy-1.2.0" } }, "adp": [ { "problemTypes": [ { "descriptions": [ { "type": "CWE", "lang": "en", "description": "CWE-noinfo Not enough information" } ] } ], "metrics": [ { "cvssV3_1": { "scope": "UNCHANGED", "version": "3.1", "baseScore": 4.4, "attackVector": "LOCAL", "baseSeverity": "MEDIUM", "vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:L", "integrityImpact": "NONE", "userInteraction": "NONE", "attackComplexity": "LOW", "availabilityImpact": "LOW", "privilegesRequired": "LOW", "confidentialityImpact": "LOW" } }, { "other": { "type": "ssvc", "content": { "timestamp": "2024-05-29T16:50:13.639283Z", "id": "CVE-2021-47555", "options": [ { "Exploitation": "none" }, { "Automatable": "no" }, { "Technical Impact": "partial" } ], "role": "CISA Coordinator", "version": "2.0.3" } } } ], "title": "CISA ADP Vulnrichment", "providerMetadata": { "orgId": "134c704f-9b21-4f2e-91b3-4a467353bcc0", "shortName": "CISA-ADP", "dateUpdated": "2024-11-04T20:18:51.592Z" } }, { "providerMetadata": { "orgId": "af854a3a-2127-422b-91ae-364da2661108", "shortName": "CVE", "dateUpdated": "2024-08-04T05:39:59.857Z" }, "title": "CVE Program Container", "references": [ { "url": "https://git.kernel.org/stable/c/5e44178864b38dd70b877985abd7d86fdb95f27d", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/6e800ee43218a56acc93676bbb3d93b74779e555", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/f7fc72a508cf115c273a7a29350069def1041890", "tags": [ "x_transferred" ] }, { "url": "https://git.kernel.org/stable/c/01d9cc2dea3fde3bad6d27f464eff463496e2b00", "tags": [ "x_transferred" ] } ] } ] } }