{"dataType":"CVE_RECORD","dataVersion":"5.2","cveMetadata":{"cveId":"CVE-2024-55916","assignerOrgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","state":"PUBLISHED","assignerShortName":"Linux","dateReserved":"2025-01-09T09:49:29.678Z","datePublished":"2025-01-11T12:35:44.800Z","dateUpdated":"2025-11-03T20:48:52.286Z"},"containers":{"cna":{"providerMetadata":{"orgId":"416baaa9-dc9f-4396-8d5f-8c081fb06d67","shortName":"Linux","dateUpdated":"2025-05-04T09:57:19.361Z"},"descriptions":[{"lang":"en","value":"In the Linux kernel, the following vulnerability has been resolved:\n\nDrivers: hv: util: Avoid accessing a ringbuffer not initialized yet\n\nIf the KVP (or VSS) daemon starts before the VMBus channel's ringbuffer is\nfully initialized, we can hit the panic below:\n\nhv_utils: Registering HyperV Utility Driver\nhv_vmbus: registering driver hv_utils\n...\nBUG: kernel NULL pointer dereference, address: 0000000000000000\nCPU: 44 UID: 0 PID: 2552 Comm: hv_kvp_daemon Tainted: G E 6.11.0-rc3+ #1\nRIP: 0010:hv_pkt_iter_first+0x12/0xd0\nCall Trace:\n...\n vmbus_recvpacket\n hv_kvp_onchannelcallback\n vmbus_on_event\n tasklet_action_common\n tasklet_action\n handle_softirqs\n irq_exit_rcu\n sysvec_hyperv_stimer0\n </IRQ>\n <TASK>\n asm_sysvec_hyperv_stimer0\n...\n kvp_register_done\n hvt_op_read\n vfs_read\n ksys_read\n __x64_sys_read\n\nThis can happen because the KVP/VSS channel callback can be invoked\neven before the channel is fully opened:\n1) as soon as hv_kvp_init() -> hvutil_transport_init() creates\n/dev/vmbus/hv_kvp, the kvp daemon can open the device file immediately and\nregister itself to the driver by writing a message KVP_OP_REGISTER1 to the\nfile (which is handled by kvp_on_msg() ->kvp_handle_handshake()) and\nreading the file for the driver's response, which is handled by\nhvt_op_read(), which calls hvt->on_read(), i.e. kvp_register_done().\n\n2) the problem with kvp_register_done() is that it can cause the\nchannel callback to be called even before the channel is fully opened,\nand when the channel callback is starting to run, util_probe()->\nvmbus_open() may have not initialized the ringbuffer yet, so the\ncallback can hit the panic of NULL pointer dereference.\n\nTo reproduce the panic consistently, we can add a \"ssleep(10)\" for KVP in\n__vmbus_open(), just before the first hv_ringbuffer_init(), and then we\nunload and reload the driver hv_utils, and run the daemon manually within\nthe 10 seconds.\n\nFix the panic by reordering the steps in util_probe() so the char dev\nentry used by the KVP or VSS daemon is not created until after\nvmbus_open() has completed. This reordering prevents the race condition\nfrom happening."}],"affected":[{"product":"Linux","vendor":"Linux","defaultStatus":"unaffected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/hv_kvp.c","drivers/hv/hv_snapshot.c","drivers/hv/hv_util.c","drivers/hv/hyperv_vmbus.h","include/linux/hyperv.h"],"versions":[{"version":"e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c","lessThan":"f091a224a2c82f1e302b1768d73bb6332f687321","status":"affected","versionType":"git"},{"version":"e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c","lessThan":"d81f4e73aff9b861671df60e5100ad25cc16fbf8","status":"affected","versionType":"git"},{"version":"e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c","lessThan":"042253c57be901bfd19f15b68267442b70f510d5","status":"affected","versionType":"git"},{"version":"e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c","lessThan":"718fe694a334be9d1a89eed22602369ac18d6583","status":"affected","versionType":"git"},{"version":"e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c","lessThan":"89fcec5e466b3ac9b376e0d621c71effa1a7983f","status":"affected","versionType":"git"},{"version":"e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c","lessThan":"3dd7a30c6d7f90afcf19e9b072f572ba524d7ec6","status":"affected","versionType":"git"},{"version":"e0fa3e5e7df61eb2c339c9f0067c202c0cdeec2c","lessThan":"07a756a49f4b4290b49ea46e089cbe6f79ff8d26","status":"affected","versionType":"git"}]},{"product":"Linux","vendor":"Linux","defaultStatus":"affected","repo":"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git","programFiles":["drivers/hv/hv_kvp.c","drivers/hv/hv_snapshot.c","drivers/hv/hv_util.c","drivers/hv/hyperv_vmbus.h","include/linux/hyperv.h"],"versions":[{"version":"4.9","status":"affected"},{"version":"0","lessThan":"4.9","status":"unaffected","versionType":"semver"},{"version":"5.4.289","lessThanOrEqual":"5.4.*","status":"unaffected","versionType":"semver"},{"version":"5.10.233","lessThanOrEqual":"5.10.*","status":"unaffected","versionType":"semver"},{"version":"5.15.176","lessThanOrEqual":"5.15.*","status":"unaffected","versionType":"semver"},{"version":"6.1.122","lessThanOrEqual":"6.1.*","status":"unaffected","versionType":"semver"},{"version":"6.6.68","lessThanOrEqual":"6.6.*","status":"unaffected","versionType":"semver"},{"version":"6.12.7","lessThanOrEqual":"6.12.*","status":"unaffected","versionType":"semver"},{"version":"6.13","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":"4.9","versionEndExcluding":"5.4.289"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"5.10.233"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"5.15.176"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"6.1.122"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"6.6.68"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"6.12.7"},{"vulnerable":true,"criteria":"cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*","versionStartIncluding":"4.9","versionEndExcluding":"6.13"}]}]}],"references":[{"url":"https://git.kernel.org/stable/c/f091a224a2c82f1e302b1768d73bb6332f687321"},{"url":"https://git.kernel.org/stable/c/d81f4e73aff9b861671df60e5100ad25cc16fbf8"},{"url":"https://git.kernel.org/stable/c/042253c57be901bfd19f15b68267442b70f510d5"},{"url":"https://git.kernel.org/stable/c/718fe694a334be9d1a89eed22602369ac18d6583"},{"url":"https://git.kernel.org/stable/c/89fcec5e466b3ac9b376e0d621c71effa1a7983f"},{"url":"https://git.kernel.org/stable/c/3dd7a30c6d7f90afcf19e9b072f572ba524d7ec6"},{"url":"https://git.kernel.org/stable/c/07a756a49f4b4290b49ea46e089cbe6f79ff8d26"}],"title":"Drivers: hv: util: Avoid accessing a ringbuffer not initialized yet","x_generator":{"engine":"bippy-1.2.0"}},"adp":[{"metrics":[{"cvssV3_1":{"scope":"UNCHANGED","version":"3.1","baseScore":5.5,"attackVector":"LOCAL","baseSeverity":"MEDIUM","vectorString":"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H","integrityImpact":"NONE","userInteraction":"NONE","attackComplexity":"LOW","availabilityImpact":"HIGH","privilegesRequired":"LOW","confidentialityImpact":"NONE"}},{"other":{"type":"ssvc","content":{"id":"CVE-2024-55916","role":"CISA Coordinator","options":[{"Exploitation":"none"},{"Automatable":"no"},{"Technical Impact":"partial"}],"version":"2.0.3","timestamp":"2025-10-01T19:55:21.065122Z"}}}],"problemTypes":[{"descriptions":[{"lang":"en","type":"CWE","cweId":"CWE-476","description":"CWE-476 NULL Pointer Dereference"}]}],"title":"CISA ADP Vulnrichment","providerMetadata":{"orgId":"134c704f-9b21-4f2e-91b3-4a467353bcc0","shortName":"CISA-ADP","dateUpdated":"2025-10-01T19:57:21.020Z"}},{"title":"CVE Program Container","references":[{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00001.html"},{"url":"https://lists.debian.org/debian-lts-announce/2025/03/msg00002.html"}],"providerMetadata":{"orgId":"af854a3a-2127-422b-91ae-364da2661108","shortName":"CVE","dateUpdated":"2025-11-03T20:48:52.286Z"}}]}}