CVE-2025-40043 (GCVE-0-2025-40043)
Vulnerability from cvelistv5 – Published: 2025-10-28 11:48 – Updated: 2026-08-05 12:07
VLAI
EPSS
VEX
Title
net: nfc: nci: Add parameter validation for packet data
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: nfc: nci: Add parameter validation for packet data
Syzbot reported an uninitialized value bug in nci_init_req, which was
introduced by commit 5aca7966d2a7 ("Merge tag
'perf-tools-fixes-for-v6.17-2025-09-16' of
git://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools").
This bug arises due to very limited and poor input validation
that was done at nic_valid_size(). This validation only
validates the skb->len (directly reflects size provided at the
userspace interface) with the length provided in the buffer
itself (interpreted as NCI_HEADER). This leads to the processing
of memory content at the address assuming the correct layout
per what opcode requires there. This leads to the accesses to
buffer of `skb_buff->data` which is not assigned anything yet.
Following the same silent drop of packets of invalid sizes at
`nic_valid_size()`, add validation of the data in the respective
handlers and return error values in case of failure. Release
the skb if error values are returned from handlers in
`nci_nft_packet` and effectively do a silent drop
Possible TODO: because we silently drop the packets, the
call to `nci_request` will be waiting for completion of request
and will face timeouts. These timeouts can get excessively logged
in the dmesg. A proper handling of them may require to export
`nci_request_cancel` (or propagate error handling from the
nft packets handlers).
Severity
8.8 (High)
Assigner
References
6 references
Impacted products
2 products
| Vendor | Product | Version | CPE status | |
|---|---|---|---|---|
| Linux | Linux |
Affected:
6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 8fcc7315a10a84264e55bb65ede10f0af20a983f
(git)
Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < bfdda0123dde406dbff62e7e9136037e97998a15 (git) Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 0ba68bea1e356f466ad29449938bea12f5f3711f (git) Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 74837bca0748763a77f77db47a0bdbe63b347628 (git) Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < c395d1e548cc68e84584ffa2e3ca9796a78bf7b9 (git) Affected: 6a2968aaf50c7a22fced77a5e24aa636281efca8 , < 9c328f54741bd5465ca1dc717c84c04242fac2e1 (git) |
guessed | |
| Linux | Linux |
Affected:
3.2
Unaffected: 0 , < 3.2 (semver) Unaffected: 5.15.195 , ≤ 5.15.* (semver) Unaffected: 6.1.156 , ≤ 6.1.* (semver) Unaffected: 6.6.112 , ≤ 6.6.* (semver) Unaffected: 6.12.53 , ≤ 6.12.* (semver) Unaffected: 6.17.3 , ≤ 6.17.* (semver) Unaffected: 6.18 , ≤ * (original_commit_for_fix) |
guessed |
{
"containers": {
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"product": "Linux",
"programFiles": [
"net/nfc/nci/ntf.c"
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"vendor": "Linux",
"versions": [
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"version": "3.2"
},
{
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"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
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"status": "unaffected",
"version": "5.15.195",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.156",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.112",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.53",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.17.*",
"status": "unaffected",
"version": "6.17.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.18",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.195",
"versionStartIncluding": "3.2",
"vulnerable": true
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{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.156",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.53",
"versionStartIncluding": "3.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.17.3",
"versionStartIncluding": "3.2",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18",
"versionStartIncluding": "3.2",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
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}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: nfc: nci: Add parameter validation for packet data\n\nSyzbot reported an uninitialized value bug in nci_init_req, which was\nintroduced by commit 5aca7966d2a7 (\"Merge tag\n\u0027perf-tools-fixes-for-v6.17-2025-09-16\u0027 of\ngit://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools\").\n\nThis bug arises due to very limited and poor input validation\nthat was done at nic_valid_size(). This validation only\nvalidates the skb-\u003elen (directly reflects size provided at the\nuserspace interface) with the length provided in the buffer\nitself (interpreted as NCI_HEADER). This leads to the processing\nof memory content at the address assuming the correct layout\nper what opcode requires there. This leads to the accesses to\nbuffer of `skb_buff-\u003edata` which is not assigned anything yet.\n\nFollowing the same silent drop of packets of invalid sizes at\n`nic_valid_size()`, add validation of the data in the respective\nhandlers and return error values in case of failure. Release\nthe skb if error values are returned from handlers in\n`nci_nft_packet` and effectively do a silent drop\n\nPossible TODO: because we silently drop the packets, the\ncall to `nci_request` will be waiting for completion of request\nand will face timeouts. These timeouts can get excessively logged\nin the dmesg. A proper handling of them may require to export\n`nci_request_cancel` (or propagate error handling from the\nnft packets handlers)."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 8.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:A - The parsed data is NCI notification payload whose RF-specific and activation parameters (ATS/RATS length byte, ATR_RES length, tech-specific params) originate from the contactless peer, so an attacker with a spoofed card or NFC emulator in proximity of a phone/POS/embedded reader supplies the malformed lengths. NFC proximity is Adjacent per kernel scoring guidance (a local unprivileged N_NCI-ldisc path also exists, but is strictly lower severity).\nAC:L - The attacker directly controls the length byte versus actual payload length and can present the malformed card/frame repeatedly until the target polls it; no race, no unpredictable memory-layout precondition is required.\nPR:N - No credentials or account on the target are needed \u2014 NFC polling activates and parses the notification automatically, and on the local variant `NCIUARTSETDRIVER` in nci_uart_tty_ioctl() has no capability check at all.\nUI:N - The NFC stack polls and processes discovery/activation notifications autonomously; the attacker brings the hostile device into range and the victim performs no action.\nS:U - The over-read, the write-back in the credits handler, and the leaked data all stay within the kernel\u0027s own security authority; no VM, IOMMU, or sandbox boundary is crossed.\nC:H - Tens of bytes past the payload \u2014 uninitialized slab tailroom and skb_shared_info, which holds kernel pointers \u2014 are copied into nfcid1/sens_res/ATS and exported to userspace via NFC netlink attributes, yielding stale-heap and kernel-pointer disclosure usable for KASLR defeat.\nI:H - `nci_core_conn_credits_ntf_packet()` writes masked bytes back into memory beyond the validated payload for up to 10 entries and adds an out-of-bounds byte into conn_info-\u003ecredits_cnt, and unvalidated data populates ndev state (nci_ver, manufact_id, remote_gb, credits), giving attacker-shapeable kernel memory/state corruption.\nA:H - Out-of-bounds slab reads can hit a redzone/adjacent object and oops (KASAN/panic_on_oops), and the commit itself notes the resulting dropped packets leave nci_request() blocking until timeout with repeated dmesg flooding, degrading the NFC stack."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-05T12:07:16.234Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
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"url": "https://git.kernel.org/stable/c/8fcc7315a10a84264e55bb65ede10f0af20a983f"
},
{
"url": "https://git.kernel.org/stable/c/bfdda0123dde406dbff62e7e9136037e97998a15"
},
{
"url": "https://git.kernel.org/stable/c/0ba68bea1e356f466ad29449938bea12f5f3711f"
},
{
"url": "https://git.kernel.org/stable/c/74837bca0748763a77f77db47a0bdbe63b347628"
},
{
"url": "https://git.kernel.org/stable/c/c395d1e548cc68e84584ffa2e3ca9796a78bf7b9"
},
{
"url": "https://git.kernel.org/stable/c/9c328f54741bd5465ca1dc717c84c04242fac2e1"
}
],
"title": "net: nfc: nci: Add parameter validation for packet data",
"x_generator": {
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}
}
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"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2025-40043",
"datePublished": "2025-10-28T11:48:22.230Z",
"dateReserved": "2025-04-16T07:20:57.154Z",
"dateUpdated": "2026-08-05T12:07:16.234Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2",
"vulnerability-lookup:meta": {
"epss": {
"cve": "CVE-2025-40043",
"date": "2026-09-30",
"epss": "0.00314",
"percentile": "0.21993"
},
"microsoft_vex": {
"current_release_date": "2025-10-29T01:03:54.000Z",
"cve": "CVE-2025-40043",
"id": "msrc_CVE-2025-40043",
"initial_release_date": "2025-10-02T00:00:00.000Z",
"product_status:known_not_affected": "1",
"source": "Microsoft CSAF VEX",
"status": "final",
"title": "net: nfc: nci: Add parameter validation for packet data",
"url": "https://msrc.microsoft.com/csaf/vex/2025/msrc_cve-2025-40043.json",
"version": "1"
},
"nvd": {
"cve": {
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{
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{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
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"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
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"version": "3.2"
},
{
"lessThan": "3.2",
"status": "unaffected",
"version": "0",
"versionType": "semver"
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{
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"status": "unaffected",
"version": "5.15.195",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.156",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.112",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
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"versionType": "semver"
},
{
"lessThanOrEqual": "6.17.*",
"status": "unaffected",
"version": "6.17.3",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
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"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
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"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: nfc: nci: Add parameter validation for packet data\n\nSyzbot reported an uninitialized value bug in nci_init_req, which was\nintroduced by commit 5aca7966d2a7 (\"Merge tag\n\u0027perf-tools-fixes-for-v6.17-2025-09-16\u0027 of\ngit://git.kernel.org/pub/scm/linux/kernel/git/perf/perf-tools\").\n\nThis bug arises due to very limited and poor input validation\nthat was done at nic_valid_size(). This validation only\nvalidates the skb-\u003elen (directly reflects size provided at the\nuserspace interface) with the length provided in the buffer\nitself (interpreted as NCI_HEADER). This leads to the processing\nof memory content at the address assuming the correct layout\nper what opcode requires there. This leads to the accesses to\nbuffer of `skb_buff-\u003edata` which is not assigned anything yet.\n\nFollowing the same silent drop of packets of invalid sizes at\n`nic_valid_size()`, add validation of the data in the respective\nhandlers and return error values in case of failure. Release\nthe skb if error values are returned from handlers in\n`nci_nft_packet` and effectively do a silent drop\n\nPossible TODO: because we silently drop the packets, the\ncall to `nci_request` will be waiting for completion of request\nand will face timeouts. These timeouts can get excessively logged\nin the dmesg. A proper handling of them may require to export\n`nci_request_cancel` (or propagate error handling from the\nnft packets handlers)."
}
],
"id": "CVE-2025-40043",
"lastModified": "2026-07-30T06:24:07.647",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "ADJACENT_NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 8.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 2.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2025-10-28T12:15:38.333",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0ba68bea1e356f466ad29449938bea12f5f3711f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/74837bca0748763a77f77db47a0bdbe63b347628"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8fcc7315a10a84264e55bb65ede10f0af20a983f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9c328f54741bd5465ca1dc717c84c04242fac2e1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/bfdda0123dde406dbff62e7e9136037e97998a15"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c395d1e548cc68e84584ffa2e3ca9796a78bf7b9"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Deferred"
}
},
"redhat_vex": {
"aggregate_severity": "None",
"current_release_date": "2026-06-30T10:25:39+00:00",
"cve": "CVE-2025-40043",
"id": "CVE-2025-40043",
"initial_release_date": "2025-10-28T00:00:00+00:00",
"product_status:known_not_affected": "274",
"source": "Red Hat CSAF VEX",
"status": "final",
"title": "kernel: net: nfc: nci: Add parameter validation for packet data",
"url": "https://security.access.redhat.com/data/csaf/v2/vex/2025/cve-2025-40043.json",
"version": "3"
}
}
}
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Experimental. This forecast is provided for visualization only and may change without notice. Do not use it for operational decisions.
Forecast uses a logistic model when the trend is rising, or an exponential decay model when the trend is falling. Fitted via linearized least squares.
Sightings
| Author | Source | Type | Date | Other |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or observed by the user.
- Confirmed: The vulnerability has been validated from an analyst's perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: The vulnerability was observed as exploited by the user who reported the sighting.
- Patched: The vulnerability was observed as successfully patched by the user who reported the sighting.
- Not exploited: The vulnerability was not observed as exploited by the user who reported the sighting.
- Not confirmed: The user expressed doubt about the validity of the vulnerability.
- Not patched: The vulnerability was not observed as successfully patched by the user who reported the sighting.
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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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