CVE-2026-98239

{"dataType": "CVE_RECORD", "dataVersion": "5.2", "cveMetadata": {"cveId": "CVE-2026-98239", "assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "state": "PUBLISHED", "assignerShortName": "Linux", "dateReserved": "2026-09-25T10:25:14.329Z", "datePublished": "2026-10-06T08:45:10.611Z", "dateUpdated": "2026-10-19T09:16:10.911Z"}, "containers": {"cna": {"providerMetadata": {"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "shortName": "Linux", "dateUpdated": "2026-10-19T09:16:10.911Z"}, "descriptions": [{"lang": "en", "value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: lan743x: fix RX checksum use-after-free\n\nlan743x_rx_process_buffer() adds each non-first receive buffer to the\nhead skb's frag_list. On the last descriptor, lan743x_rx_trim_skb()\nlinearizes the head and frees the fragment skb metadata.\n\nThe checksum-success path then writes ip_summed through the local skb\npointer, which still points to the final fragment. This causes a\nuse-after-free write when a packet spans more than one receive buffer.\n\nSet ip_summed on the surviving head skb instead. Multi-buffer receive\ncan occur after a live MTU increase because existing ring entries keep\ntheir old buffer size until they are replenished.\n\nA KUnit test invoking lan743x_rx_process_buffer() with a two-buffer\npacket produced a one-byte KASAN use-after-free write before this change.\nThe same test passed after the change. The driver object also builds\nwith W=1. This was not tested on physical LAN743x hardware."}], "metrics": [{"cvssV3_1": {"version": "3.1", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "baseScore": 8.1, "baseSeverity": "HIGH"}, "scenarios": [{"lang": "en", "value": "AV:N - The UAF write runs in lan743x_rx_process_buffer() (NAPI RX) while it handles an ordinary received Ethernet/IP frame from a remote sender. The sender's frame must be larger than the pre-change buffer size so the chip spreads it across several ring descriptors, which a routed jumbo-MTU path can deliver.\nAC:H - Buffers are sized mtu+ETH_HLEN+FCS+2 and the MAC caps frames at mtu+18 (MAC_RX_FSE_), so multi-buffer frames only occur after an admin raises the MTU on a live interface, while stale ring entries remain, or through the chip's occasional extra-buffer quirk. The remote attacker cannot produce either condition.\nPR:N - The trigger is a received frame with a valid checksum handled in the NAPI poll path, lan743x_rx_napi_poll -> lan743x_rx_process_buffer. The sender needs no authentication or credentials on the host.\nUI:N - Once the ring holds stale smaller buffers, no user on the victim needs to do anything; sending the oversized frame triggers the stale write. The admin's MTU change is already counted in AC:H.\nS:U - The freed sk_buff and the corrupted slab memory are inside the kernel itself; no VM, IOMMU or sandbox boundary is crossed.\nC:H - After skb_linearize() in lan743x_rx_trim_skb() frees the frag_list skb, its skbuff_head_cache slot can be reused by another skb. The stale write then hits a live object the attacker can steer with packet timing, which counts as a use-after-free per the scoring guidance.\nI:H - skb->ip_summed = CHECKSUM_UNNECESSARY is written into a freed sk_buff. If the slot has been reallocated, this corrupts another live skb and can make the stack accept forged or corrupted packets without checking their checksums. It is heap memory corruption.\nA:H - Writing into a freed and possibly reused sk_buff from the RX softirq can corrupt slab state and oops or panic the kernel; KASAN flagged the write in the author's KUnit reproducer."}]}], "affected": [{"product": "Linux", "vendor": "Linux", "defaultStatus": "unaffected", "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "programFiles": ["drivers/net/ethernet/microchip/lan743x_main.c"], "versions": [{"version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "lessThan": "0e52886c4324c9897c2c62f92be3dc8316cee67e", "status": "affected", "versionType": "git"}, {"version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "lessThan": "a58024835c704419bb46d2a34e5223f65605f958", "status": "affected", "versionType": "git"}, {"version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "lessThan": "6fe5c3a2503983abb431d93faeadfc7f5e6a7e33", "status": "affected", "versionType": "git"}, {"version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "lessThan": "5c216bfa9fb7b36804485e67975e9c98055b31ef", "status": "affected", "versionType": "git"}, {"version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "lessThan": "161a403c8625e152de03d1da22bbf9cda6dc9f9f", "status": "affected", "versionType": "git"}, {"version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "lessThan": "a9ce4053dc945c5372dedba5017ee675b30dc0c5", "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/net/ethernet/microchip/lan743x_main.c"], "versions": [{"version": "6.1", "status": "affected"}, {"version": "0", "lessThan": "6.1", "status": "unaffected", "versionType": "semver"}, {"version": "6.1.189", "lessThanOrEqual": "6.1.*", "status": "unaffected", "versionType": "semver"}, {"version": "6.6.158", "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": "6.1", "versionEndExcluding": "6.1.189"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.6.158"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.12.112"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "6.18.54"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.2.8"}, {"vulnerable": true, "criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*", "versionStartIncluding": "6.1", "versionEndExcluding": "7.3"}]}]}], "references": [{"url": "https://git.kernel.org/stable/c/0e52886c4324c9897c2c62f92be3dc8316cee67e"}, {"url": "https://git.kernel.org/stable/c/a58024835c704419bb46d2a34e5223f65605f958"}, {"url": "https://git.kernel.org/stable/c/6fe5c3a2503983abb431d93faeadfc7f5e6a7e33"}, {"url": "https://git.kernel.org/stable/c/5c216bfa9fb7b36804485e67975e9c98055b31ef"}, {"url": "https://git.kernel.org/stable/c/161a403c8625e152de03d1da22bbf9cda6dc9f9f"}, {"url": "https://git.kernel.org/stable/c/a9ce4053dc945c5372dedba5017ee675b30dc0c5"}], "title": "net: lan743x: fix RX checksum use-after-free", "x_generator": {"engine": "bippy-1.2.0"}}}}

{}

{"affected": [{"affectedData": [{"defaultStatus": "unaffected", "product": "Linux", "programFiles": ["drivers/net/ethernet/microchip/lan743x_main.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"lessThan": "0e52886c4324c9897c2c62f92be3dc8316cee67e", "status": "affected", "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "versionType": "git"}, {"lessThan": "a58024835c704419bb46d2a34e5223f65605f958", "status": "affected", "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "versionType": "git"}, {"lessThan": "6fe5c3a2503983abb431d93faeadfc7f5e6a7e33", "status": "affected", "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "versionType": "git"}, {"lessThan": "5c216bfa9fb7b36804485e67975e9c98055b31ef", "status": "affected", "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "versionType": "git"}, {"lessThan": "161a403c8625e152de03d1da22bbf9cda6dc9f9f", "status": "affected", "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "versionType": "git"}, {"lessThan": "a9ce4053dc945c5372dedba5017ee675b30dc0c5", "status": "affected", "version": "cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a", "versionType": "git"}]}, {"defaultStatus": "affected", "product": "Linux", "programFiles": ["drivers/net/ethernet/microchip/lan743x_main.c"], "repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git", "vendor": "Linux", "versions": [{"status": "affected", "version": "6.1"}, {"lessThan": "6.1", "status": "unaffected", "version": "0", "versionType": "semver"}, {"lessThanOrEqual": "6.1.*", "status": "unaffected", "version": "6.1.189", "versionType": "semver"}, {"lessThanOrEqual": "6.6.*", "status": "unaffected", "version": "6.6.158", "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\nnet: lan743x: fix RX checksum use-after-free\n\nlan743x_rx_process_buffer() adds each non-first receive buffer to the\nhead skb's frag_list. On the last descriptor, lan743x_rx_trim_skb()\nlinearizes the head and frees the fragment skb metadata.\n\nThe checksum-success path then writes ip_summed through the local skb\npointer, which still points to the final fragment. This causes a\nuse-after-free write when a packet spans more than one receive buffer.\n\nSet ip_summed on the surviving head skb instead. Multi-buffer receive\ncan occur after a live MTU increase because existing ring entries keep\ntheir old buffer size until they are replenished.\n\nA KUnit test invoking lan743x_rx_process_buffer() with a two-buffer\npacket produced a one-byte KASAN use-after-free write before this change.\nThe same test passed after the change. The driver object also builds\nwith W=1. This was not tested on physical LAN743x hardware."}], "id": "CVE-2026-98239", "lastModified": "2026-10-19T10:18:24.750", "metrics": {"cvssMetricV31": [{"cvssData": {"attackComplexity": "HIGH", "attackVector": "NETWORK", "availabilityImpact": "HIGH", "baseScore": 8.1, "baseSeverity": "HIGH", "confidentialityImpact": "HIGH", "integrityImpact": "HIGH", "privilegesRequired": "NONE", "scope": "UNCHANGED", "userInteraction": "NONE", "vectorString": "CVSS:3.1/AV:N/AC:H/PR:N/UI:N/S:U/C:H/I:H/A:H", "version": "3.1"}, "exploitabilityScore": 2.2, "impactScore": 5.9, "source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "type": "Secondary"}]}, "published": "2026-10-06T09:18:11.803", "references": [{"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/0e52886c4324c9897c2c62f92be3dc8316cee67e"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/161a403c8625e152de03d1da22bbf9cda6dc9f9f"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/5c216bfa9fb7b36804485e67975e9c98055b31ef"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/6fe5c3a2503983abb431d93faeadfc7f5e6a7e33"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a58024835c704419bb46d2a34e5223f65605f958"}, {"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "url": "https://git.kernel.org/stable/c/a9ce4053dc945c5372dedba5017ee675b30dc0c5"}], "sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67", "vulnStatus": "Received"}

{"bugzilla": {"description": "kernel: net: lan743x: fix RX checksum use-after-free", "id": "2546529", "url": "https://bugzilla.redhat.com/show_bug.cgi?id=2546529"}, "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:\nnet: lan743x: fix RX checksum use-after-free\nlan743x_rx_process_buffer() adds each non-first receive buffer to the\nhead skb's frag_list. On the last descriptor, lan743x_rx_trim_skb()\nlinearizes the head and frees the fragment skb metadata.\nThe checksum-success path then writes ip_summed through the local skb\npointer, which still points to the final fragment. This causes a\nuse-after-free write when a packet spans more than one receive buffer.\nSet ip_summed on the surviving head skb instead. Multi-buffer receive\ncan occur after a live MTU increase because existing ring entries keep\ntheir old buffer size until they are replenished.\nA KUnit test invoking lan743x_rx_process_buffer() with a two-buffer\npacket produced a one-byte KASAN use-after-free write before this change.\nThe same test passed after the change. The driver object also builds\nwith W=1. This was not tested on physical LAN743x hardware.", "A flaw was found in the Linux kernel's LAN743x network device driver. This vulnerability allows an attacker capable of transmitting network traffic to an affected system to cause a Denial of Service (DoS) or memory corruption. The issue occurs because the driver attempts to update checksum information on a packet buffer that has already been freed during multi-buffer receive handling, resulting in a use-after-free condition."], "name": "CVE-2026-98239", "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": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:8", "fix_state": "Not affected", "package_name": "kernel-rt", "product_name": "Red Hat Enterprise Linux 8"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not affected", "package_name": "kernel", "product_name": "Red Hat Enterprise Linux 9"}, {"cpe": "cpe:/o:redhat:enterprise_linux:9", "fix_state": "Not 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": "Not 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-2026-98239\nhttps://nvd.nist.gov/vuln/detail/CVE-2026-98239\nhttps://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-98239.mbox"], "threat_severity": "Moderate"}

{"affected": [{"configurations": [{"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a,0e52886c4324c9897c2c62f92be3dc8316cee67e)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a,a58024835c704419bb46d2a34e5223f65605f958)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a,6fe5c3a2503983abb431d93faeadfc7f5e6a7e33)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a,5c216bfa9fb7b36804485e67975e9c98055b31ef)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a,161a403c8625e152de03d1da22bbf9cda6dc9f9f)"}}, {"platform": null, "status": "affected", "versions": {"scheme": "code_commit", "value": "[cd6910501cfd9a3bdff2f5fc33c9f3cf165ca54a,a9ce4053dc945c5372dedba5017ee675b30dc0c5)"}}], "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": "6.1"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[0,6.1)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.1.189,6.2.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.6.158,6.7.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.12.112,6.13.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "value": "[6.18.54,6.19.0)"}}, {"platform": null, "status": "unaffected", "versions": {"scheme": "semver", "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": "2026-10-06T14:45:18.429686+00:00", "updated": "2026-10-09T14:00:07.542718+00:00", "vendors": ["linux", "linux$PRODUCT$linux_kernel"], "weaknesses": ["CWE-825"]}