FKIE_CVE-2025-39673
Vulnerability from fkie_nvd - Published: 2025-09-05 18:15 - Updated: 2026-07-30 06:23
Severity
9.8 (Critical) - CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H
4.7 (Medium) - CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H
4.7 (Medium) - CVSS:3.1/
Summary
In the Linux kernel, the following vulnerability has been resolved:
ppp: fix race conditions in ppp_fill_forward_path
ppp_fill_forward_path() has two race conditions:
1. The ppp->channels list can change between list_empty() and
list_first_entry(), as ppp_lock() is not held. If the only channel
is deleted in ppp_disconnect_channel(), list_first_entry() may
access an empty head or a freed entry, and trigger a panic.
2. pch->chan can be NULL. When ppp_unregister_channel() is called,
pch->chan is set to NULL before pch is removed from ppp->channels.
Fix these by using a lockless RCU approach:
- Use list_first_or_null_rcu() to safely test and access the first list
entry.
- Convert list modifications on ppp->channels to their RCU variants and
add synchronize_net() after removal.
- Check for a NULL pch->chan before dereferencing it.
References
Impacted products
| Vendor | Product | Version | |
|---|---|---|---|
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | * | |
| linux | linux_kernel | 6.17 | |
| linux | linux_kernel | 6.17 | |
| debian | debian_linux | 11.0 |
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"drivers/net/ppp/ppp_generic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "9a1969fbffc1f1900d92d7594b1b7d8d72ef3dc7",
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"versionType": "git"
},
{
"lessThan": "0f1630be6fcca3f0c63e4b242ad202e5cde28a40",
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"versionType": "git"
},
{
"lessThan": "ca18d751bcc9faf5b7e82e9fae1223d103928181",
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"versionType": "git"
},
{
"lessThan": "94731cc551e29511d85aa8dec61a6c071b1f2430",
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"versionType": "git"
},
{
"lessThan": "f97f6475fdcb3c28ff3c55cc4b7bde632119ec08",
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"versionType": "git"
},
{
"lessThan": "0417adf367a0af11adf7ace849af4638cfb573f7",
"status": "affected",
"version": "f6efc675c9dd8d93f826b79ae7e33e03301db609",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"drivers/net/ppp/ppp_generic.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.13"
},
{
"lessThan": "5.13",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.190",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.149",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.103",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.44",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.16.*",
"status": "unaffected",
"version": "6.16.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "6.17",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
},
{
"affectedData": [
{
"defaultStatus": "unknown",
"product": "SIMATIC CN 4100",
"vendor": "Siemens",
"versions": [
{
"lessThan": "V5.0",
"status": "affected",
"version": "0",
"versionType": "custom"
}
]
}
],
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e"
}
],
"configurations": [
{
"nodes": [
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{
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{
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],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nppp: fix race conditions in ppp_fill_forward_path\n\nppp_fill_forward_path() has two race conditions:\n\n1. The ppp-\u003echannels list can change between list_empty() and\n list_first_entry(), as ppp_lock() is not held. If the only channel\n is deleted in ppp_disconnect_channel(), list_first_entry() may\n access an empty head or a freed entry, and trigger a panic.\n\n2. pch-\u003echan can be NULL. When ppp_unregister_channel() is called,\n pch-\u003echan is set to NULL before pch is removed from ppp-\u003echannels.\n\nFix these by using a lockless RCU approach:\n- Use list_first_or_null_rcu() to safely test and access the first list\n entry.\n- Convert list modifications on ppp-\u003echannels to their RCU variants and\n add synchronize_net() after removal.\n- Check for a NULL pch-\u003echan before dereferencing it."
}
],
"id": "CVE-2025-39673",
"lastModified": "2026-07-30T06:23:39.090",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "NETWORK",
"availabilityImpact": "HIGH",
"baseScore": 9.8,
"baseSeverity": "CRITICAL",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "NONE",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
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"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
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{
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"attackVector": "LOCAL",
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"confidentialityImpact": "NONE",
"integrityImpact": "NONE",
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"vectorString": "CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:N/I:N/A:H",
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},
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"impactScore": 3.6,
"source": "nvd@nist.gov",
"type": "Primary"
}
]
},
"published": "2025-09-05T18:15:43.230",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"tags": [
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"url": "https://git.kernel.org/stable/c/0417adf367a0af11adf7ace849af4638cfb573f7"
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{
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"tags": [
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"url": "https://git.kernel.org/stable/c/f97f6475fdcb3c28ff3c55cc4b7bde632119ec08"
},
{
"source": "af854a3a-2127-422b-91ae-364da2661108",
"tags": [
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"url": "https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html"
},
{
"source": "0b142b55-0307-4c5a-b3c9-f314f3fb7c5e",
"url": "https://cert-portal.siemens.com/productcert/html/ssa-032379.html"
}
],
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"vulnStatus": "Modified",
"weaknesses": [
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{
"lang": "en",
"value": "CWE-362"
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],
"source": "nvd@nist.gov",
"type": "Primary"
}
]
}
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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
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