CVE-2026-98173

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98173", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.322Z", "datePublished": "2026-10-06T08:44:17.567Z", "dateUpdated": "2026-10-30T12:37:52.156Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-30T12:37:52.156Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nsmb: client: fix use-after-free of iface in cifs_try_adding_channels()\n\ncifs_try_adding_channels() iterates ses->iface_list with\nlist_for_each_entry_safe_from(), which captures the next entry\n(niface) under iface_lock. The loop body then drops iface_lock for\nthe whole duration of cifs_ses_add_channel().\n\nA concurrent interface refresh (SMB3_request_interfaces() ->\nparse_server_interfaces()) marks all ifaces inactive and removes and\nfrees any that are not re-advertised via list_del() + kref_put(),\nwhere release_iface() is a bare kfree(). Since niface typically has\nno channel holding a reference, the list reference is its last and it\ncan be freed inside the unlocked window. On continue, the iterator\nadvance step then dereferences niface->iface_head.next, and the loop\nbody reads iface->rdma_capable/is_active, both on freed memory.\n\nFix this by never keeping an unreferenced list pointer across the\nunlocked window. Each channel attempt now re-scans the list from the\nhead under iface_lock, takes a kref on the selected candidate, and\npasses only that referenced candidate to cifs_ses_add_channel().\nweight_fulfilled still tracks selection progress, so restarting the\nscan preserves the original weighted distribution and the\nweight_fulfilled-before-kref_put ordering on the failure path.\n\nAdd a per-pass attempts cap so a flapping interface refresh cannot\nkeep the inner loop spinning within a single tries increment."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H", "baseScore": 7.5, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - A malicious SMB server sends the bad data over TCP/445 in its FSCTL_QUERY_NETWORK_INTERFACE_INFO responses. A later response leaves out an interface, so parse_server_interfaces() does list_del() and kref_put() and frees it. cifs_try_adding_channels() still holds niface after dropping iface_lock for cifs_ses_add_channel(), and that pointer now refers to freed memory.\nAC:H - Multichannel is off by default (multichannel=false, max_channels=1), so the victim must mount with multichannel or max_channels>1. The server also has to line up a refresh from the 600s smb2_query_server_interfaces worker with the unlocked add-channel window. It can stall channel setup and force reconnects to retry, but it does not schedule the worker.\nPR:N - The attacker only runs a rogue SMB server and needs no account or privilege on the victim client. The interface list is server-supplied data the client trusts during the session it opened.\nUI:R - A victim or admin has to mount a share from the attacker's server with multichannel turned on. CIFS mounts are not FS_USERNS_MOUNT, so the attacker cannot set up the client side alone.\nS:U - The memory corruption stays inside the client kernel's own security authority. No VM or other trust boundary is crossed.\nC:H - The loop continues through freed niface->iface_head.next and reads iface->rdma_capable, is_active, speed and sockaddr from the freed cifs_server_iface. The attacker can refill that heap object with their own data, which lets the kernel follow attacker-chosen pointers.\nI:H - Once the freed entry is reallocated, the loop does kref_get() and weight_fulfilled++/num_channels++ through the stale or forged iface pointer. That is a kernel write at a location the attacker influences, and cifs_ses_add_channel() then uses the forged object.\nA:H - Dereferencing the freed list entry in cifs_try_adding_channels() can oops or panic the client. The server can force reconnects to re-enter this path repeatedly."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/sess.c"], "versions": [{"version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "lessThan": "93e8a49adb2a575202c5ee766435eff2f9f95f5b", "status": "affected", "versionType": "git"}, {"version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "lessThan": "ee0d8f83d68f6e6509f092c997ccab3c8c801538", "status": "affected", "versionType": "git"}, {"version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "lessThan": "c941f1ebfd26f683de81091473f3596a218abff0", "status": "affected", "versionType": "git"}, {"version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "lessThan": "e99040e5e9c60441e6b4725e1a7b88c3106ae903", "status": "affected", "versionType": "git"}, {"version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "lessThan": "ec36b38e65596950e6c29bed7dfc90b98707c19c", "status": "affected", "versionType": "git"}, {"version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "lessThan": "d034e836eefd7ce75e588f7031cffbeec594f5ac", "status": "affected", "versionType": "git"}]}, {"product": "Linux", "vendor": "Linux", "defaultStatus": "affected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["fs/smb/client/sess.c"], "versions": [{"version": "5.19", "status": "affected"}, {"version": "0", "lessThan": "5.19", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.191", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.160", "lessThanOrEqual": "6.6.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.12.112", "lessThanOrEqual": "6.12.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.18.54", "lessThanOrEqual": "6.18.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.2.8", "lessThanOrEqual": "7.2.*", "status": "unaffected", "versionType": "semver"}, {"version": "7.3", "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": "5.19", "versionEndExcluding": "6.1.191"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.6.160"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.12.112"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "6.18.54"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "7.2.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "5.19", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/93e8a49adb2a575202c5ee766435eff2f9f95f5b"}, {"url": "https://git.kernel.org/stable/c/ee0d8f83d68f6e6509f092c997ccab3c8c801538"}, {"url": "https://git.kernel.org/stable/c/c941f1ebfd26f683de81091473f3596a218abff0"}, {"url": "https://git.kernel.org/stable/c/e99040e5e9c60441e6b4725e1a7b88c3106ae903"}, {"url": "https://git.kernel.org/stable/c/ec36b38e65596950e6c29bed7dfc90b98707c19c"}, {"url": "https://git.kernel.org/stable/c/d034e836eefd7ce75e588f7031cffbeec594f5ac"}], "title": "smb: client: fix use-after-free of iface in cifs_try_adding_channels()", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["fs/smb/client/sess.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "93e8a49adb2a575202c5ee766435eff2f9f95f5b", "status": "affected", "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "versionType": "git"}, {"lessThan": "ee0d8f83d68f6e6509f092c997ccab3c8c801538", "status": "affected", "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "versionType": "git"}, {"lessThan": "c941f1ebfd26f683de81091473f3596a218abff0", "status": "affected", "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "versionType": "git"}, {"lessThan": "e99040e5e9c60441e6b4725e1a7b88c3106ae903", "status": "affected", "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "versionType": "git"}, {"lessThan": "ec36b38e65596950e6c29bed7dfc90b98707c19c", "status": "affected", "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "versionType": "git"}, {"lessThan": "d034e836eefd7ce75e588f7031cffbeec594f5ac", "status": "affected", "version": "aa45dadd34e44fcd6a9df4b395bee5b5633b4cec", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["fs/smb/client/sess.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "5.19"}, {"lessThan": "5.19", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.191", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.160", "versionType": "semver"}, {"lessThanOrEqual": "6.12.*", "status": "unaffected", "version": "6.12.112", "versionType": "semver"}, {"lessThanOrEqual": "6.18.*", "status": "unaffected", "version": "6.18.54", "versionType": "semver"}, {"lessThanOrEqual": "7.2.*", "status": "unaffected", "version": "7.2.8", "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\nsmb: client: fix use-after-free of iface in cifs_try_adding_channels()\n\ncifs_try_adding_channels() iterates ses->iface_list with\nlist_for_each_entry_safe_from(), which captures the next entry\n(niface) under iface_lock. The loop body then drops iface_lock for\nthe whole duration of cifs_ses_add_channel().\n\nA concurrent interface refresh (SMB3_request_interfaces() ->\nparse_server_interfaces()) marks all ifaces inactive and removes and\nfrees any that are not re-advertised via list_del() + kref_put(),\nwhere release_iface() is a bare kfree(). Since niface typically has\nno channel holding a reference, the list reference is its last and it\ncan be freed inside the unlocked window. On continue, the iterator\nadvance step then dereferences niface->iface_head.next, and the loop\nbody reads iface->rdma_capable/is_active, both on freed memory.\n\nFix this by never keeping an unreferenced list pointer across the\nunlocked window. Each channel attempt now re-scans the list from the\nhead under iface_lock, takes a kref on the selected candidate, and\npasses only that referenced candidate to cifs_ses_add_channel().\nweight_fulfilled still tracks selection progress, so restarting the\nscan preserves the original weighted distribution and the\nweight_fulfilled-before-kref_put ordering on the failure path.\n\nAdd a per-pass attempts cap so a flapping interface refresh cannot\nkeep the inner loop spinning within a single tries increment."}], "id": "CVE-2026-98173", "lastModified": "2026-10-30T13:21:11.653", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 7.5, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "REQUIRED", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:R/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 1.6, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-10-06T09:17:59.060", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/93e8a49adb2a575202c5ee766435eff2f9f95f5b"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/c941f1ebfd26f683de81091473f3596a218abff0"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/d034e836eefd7ce75e588f7031cffbeec594f5ac"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/e99040e5e9c60441e6b4725e1a7b88c3106ae903"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ec36b38e65596950e6c29bed7dfc90b98707c19c"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/ee0d8f83d68f6e6509f092c997ccab3c8c801538"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: smb: client: fix use-after-free of iface in cifs_try_adding_channels()", "id": "2546481", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2546481"}, "csaw": false, "cvss3": {"cvss3_base_score": "7.0", "cvss3_scoring_vector": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H", "status": "draft"}, "cwe": "CWE-825", "details": ["In the Linux kernel, the following vulnerability has been resolved:\nsmb: client: fix use-after-free of iface in cifs_try_adding_channels()\ncifs_try_adding_channels() iterates ses->iface_list with\nlist_for_each_entry_safe_from(), which captures the next entry\n(niface) under iface_lock. The loop body then drops iface_lock for\nthe whole duration of cifs_ses_add_channel().\nA concurrent interface refresh (SMB3_request_interfaces() ->\nparse_server_interfaces()) marks all ifaces inactive and removes and\nfrees any that are not re-advertised via list_del() + kref_put(),\nwhere release_iface() is a bare kfree(). Since niface typically has\nno channel holding a reference, the list reference is its last and it\ncan be freed inside the unlocked window. On continue, the iterator\nadvance step then dereferences niface->iface_head.next, and the loop\nbody reads iface->rdma_capable/is_active, both on freed memory.\nFix this by never keeping an unreferenced list pointer across the\nunlocked window. Each channel attempt now re-scans the list from the\nhead under iface_lock, takes a kref on the selected candidate, and\npasses only that referenced candidate to cifs_ses_add_channel().\nweight_fulfilled still tracks selection progress, so restarting the\nscan preserves the original weighted distribution and the\nweight_fulfilled-before-kref_put ordering on the failure path.\nAdd a per-pass attempts cap so a flapping interface refresh cannot\nkeep the inner loop spinning within a single tries increment.", "A flaw was found in the Linux kernel's SMB client. A race condition in multichannel connection management allows network interface structures to be freed while still in use during concurrent interface refreshes. A malicious server or an attacker triggering interface updates can exploit this use-after-free vulnerability to cause a denial of service (DoS) or potentially corrupt kernel memory."], "name": "CVE-2026-98173", "package_state": [{"cpe": "cpe:/o:redhat:enterprise_linux:10", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 10"}, {"cpe": "cpe:/o:redhat:enterprise_linux:6", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 6"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:7", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 7"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Not affected", "package_name": "openshift/ose-rhel-coreos-8", "product_name": "Red Hat OpenShift Container Platform 4"}, {"cpe": "cpe:/a:redhat:openshift:4", "fix_state": "Affected", "package_name": "openshift/ose-rhel-coreos-9", "product_name": "Red Hat OpenShift Container Platform 4"}], "public_date": "2026-10-06T00:00:00Z", "references": ["https://www.cve.org/CVERecord?id=CVE-2026-98173\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98173\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98173.mbox"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa45dadd34e44fcd6a9df4b395bee5b5633b4cec,c941f1ebfd26f683de81091473f3596a218abff0)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa45dadd34e44fcd6a9df4b395bee5b5633b4cec,e99040e5e9c60441e6b4725e1a7b88c3106ae903)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa45dadd34e44fcd6a9df4b395bee5b5633b4cec,ec36b38e65596950e6c29bed7dfc90b98707c19c)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[aa45dadd34e44fcd6a9df4b395bee5b5633b4cec,d034e836eefd7ce75e588f7031cffbeec594f5ac)"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}, {"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "generic", "value": "5.19"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[0,5.19)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.12.112,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[6.18.54,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.2.8,7.3.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "generic", "value": "[7.3-rc4,*]"}}], "enrichment": {"confidence": 99.0, "confidence_source": "inferred", "scores": [{"score": 99.0, "source": "inferred"}, {"score": 100.0, "source": "matching"}]}, "original": {"product": "Linux", "source": "cna", "vendor": "Linux"}, "product": "linux_kernel", "vendor": "linux"}], "created": "2026-10-06T13:15:15.866257+00:00", "updated": "2026-10-08T14:30:18.948658+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-825"]}