FKIE_CVE-2025-21731
Vulnerability from fkie_nvd - Published: 2025-02-27 02:15 - Updated: 2026-07-14 13:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
nbd: don't allow reconnect after disconnect
Following process can cause nbd_config UAF:
1) grab nbd_config temporarily;
2) nbd_genl_disconnect() flush all recv_work() and release the
initial reference:
nbd_genl_disconnect
nbd_disconnect_and_put
nbd_disconnect
flush_workqueue(nbd->recv_workq)
if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...))
nbd_config_put
-> due to step 1), reference is still not zero
3) nbd_genl_reconfigure() queue recv_work() again;
nbd_genl_reconfigure
config = nbd_get_config_unlocked(nbd)
if (!config)
-> succeed
if (!test_bit(NBD_RT_BOUND, ...))
-> succeed
nbd_reconnect_socket
queue_work(nbd->recv_workq, &args->work)
4) step 1) release the reference;
5) Finially, recv_work() will trigger UAF:
recv_work
nbd_config_put(nbd)
-> nbd_config is freed
atomic_dec(&config->recv_threads)
-> UAF
Fix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so
that nbd_genl_reconfigure() will fail.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/block/nbd.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "e70a578487a47d7cf058904141e586684d1c3381",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
},
{
"lessThan": "6bef6222a3f6c7adb6396f77f25a3579d821b09a",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
},
{
"lessThan": "e3be8862d73cac833e0fb7602636c19c6cb94b11",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
},
{
"lessThan": "e7343fa33751cb07c1c56b666bf37cfca357130e",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
},
{
"lessThan": "d208d2c52b652913b5eefc8ca434b0d6b757f68f",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
},
{
"lessThan": "a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
},
{
"lessThan": "9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
},
{
"lessThan": "844b8cdc681612ff24df62cdefddeab5772fadf1",
"status": "affected",
"version": "b7aa3d39385dc2d95899f9e379623fef446a2acd",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/block/nbd.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.12"
},
{
"lessThan": "4.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.4.*",
"status": "unaffected",
"version": "5.4.291",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.235",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.179",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.129",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.76",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.13.*",
"status": "unaffected",
"version": "6.13.2",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.14",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
},
{
"defaultStatus": "unknown",
"product": "SIPLUS S7-1500 CPU 1518-4 PN/DP MFP",
"vendor": "Siemens",
"versions": [
{
"lessThan": "*",
"status": "affected",
"version": "V3.1.6",
"versionType": "custom"
}
]
}
],
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
}
],
"configurations": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "7B038092-73B0-4839-99CE-440987948ED1",
"versionEndExcluding": "5.4.291",
"versionStartIncluding": "4.12",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "545121FA-DE31-4154-9446-C2000FB4104D",
"versionEndExcluding": "5.10.235",
"versionStartIncluding": "5.5",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "C708062C-4E1B-465F-AE6D-C09C46400875",
"versionEndExcluding": "5.15.179",
"versionStartIncluding": "5.11",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "2DA5009C-C9B9-4A1D-9B96-78427E8F232C",
"versionEndExcluding": "6.1.129",
"versionStartIncluding": "5.16",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "A6D70701-9CB6-4222-A957-00A419878993",
"versionEndExcluding": "6.6.76",
"versionStartIncluding": "6.2",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "2897389C-A8C3-4D69-90F2-E701B3D66373",
"versionEndExcluding": "6.12.13",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"matchCriteriaId": "6D4116B1-1BFD-4F23-BA84-169CC05FC5A3",
"versionEndExcluding": "6.13.2",
"versionStartIncluding": "6.13",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnbd: don\u0027t allow reconnect after disconnect\n\nFollowing process can cause nbd_config UAF:\n\n1) grab nbd_config temporarily;\n\n2) nbd_genl_disconnect() flush all recv_work() and release the\ninitial reference:\n\n nbd_genl_disconnect\n nbd_disconnect_and_put\n nbd_disconnect\n flush_workqueue(nbd-\u003erecv_workq)\n if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...))\n nbd_config_put\n -\u003e due to step 1), reference is still not zero\n\n3) nbd_genl_reconfigure() queue recv_work() again;\n\n nbd_genl_reconfigure\n config = nbd_get_config_unlocked(nbd)\n if (!config)\n -\u003e succeed\n if (!test_bit(NBD_RT_BOUND, ...))\n -\u003e succeed\n nbd_reconnect_socket\n queue_work(nbd-\u003erecv_workq, \u0026args-\u003ework)\n\n4) step 1) release the reference;\n\n5) Finially, recv_work() will trigger UAF:\n\n recv_work\n nbd_config_put(nbd)\n -\u003e nbd_config is freed\n atomic_dec(\u0026config-\u003erecv_threads)\n -\u003e UAF\n\nFix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so\nthat nbd_genl_reconfigure() will fail."
},
{
"lang": "es",
"value": "En el kernel de Linux, se ha resuelto la siguiente vulnerabilidad: nbd: no permitir la reconexi\u00f3n despu\u00e9s de la desconexi\u00f3n El siguiente proceso puede causar el nbd_config UAF: 1) grab nbd_config temporarily; 2) nbd_genl_disconnect() flush all recv_work() and release the initial reference: nbd_genl_disconnect nbd_disconnect_and_put nbd_disconnect flush_workqueue(nbd-\u0026gt;recv_workq) if (test_and_clear_bit(NBD_RT_HAS_CONFIG_REF, ...)) nbd_config_put -\u0026gt; due to step 1), reference is still not zero 3) nbd_genl_reconfigure() queue recv_work() again; nbd_genl_reconfigure config = nbd_get_config_unlocked(nbd) if (!config) -\u0026gt; succeed if (!test_bit(NBD_RT_BOUND, ...)) -\u0026gt; succeed nbd_reconnect_socket queue_work(nbd-\u0026gt;recv_workq, \u0026amp;args-\u0026gt;work) 4) step 1) release the reference; 5) Finially, recv_work() will trigger UAF: recv_work nbd_config_put(nbd) -\u0026gt; nbd_config is freed atomic_dec(\u0026amp;config-\u0026gt;recv_threads) -\u0026gt; UAF Fix the problem by clearing NBD_RT_BOUND in nbd_genl_disconnect(), so that nbd_genl_reconfigure() will fail. "
}
],
"id": "CVE-2025-21731",
"lastModified": "2026-07-14T13:17:22.003",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
],
"ssvcV203": [
{
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"ssvcData": {
"id": "CVE-2025-21731",
"options": [
{
"exploitation": "none"
},
{
"automatable": "no"
},
{
"technicalImpact": "total"
}
],
"role": "CISA Coordinator",
"timestamp": "2025-02-27T17:58:00.860096Z",
"version": "2.0.3"
}
}
]
},
"published": "2025-02-27T02:15:16.833",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/6bef6222a3f6c7adb6396f77f25a3579d821b09a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/844b8cdc681612ff24df62cdefddeab5772fadf1"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/9793bd5ae4bdbdb2dde401a3cab94a6bfd05e302"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/a8ee6ecde2b7bfb58c8a3afe8a9d2b848f580739"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/d208d2c52b652913b5eefc8ca434b0d6b757f68f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/e3be8862d73cac833e0fb7602636c19c6cb94b11"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/e70a578487a47d7cf058904141e586684d1c3381"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
"Patch"
],
"url": "https://git.kernel.org/stable/c/e7343fa33751cb07c1c56b666bf37cfca357130e"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://lists.debian.org/debian-lts-announce/2025/03/msg00028.html"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"url": "https://lists.debian.org/debian-lts-announce/2025/05/msg00030.html"
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-019113.html"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Modified",
"weaknesses": [
{
"description": [
{
"lang": "en",
"value": "CWE-416"
}
],
"source": "134c704f-9b21-4f2e-91b3-4a467353bcc0",
"type": "Secondary"
}
]
}
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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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