FKIE_CVE-2026-74630
Vulnerability from fkie_nvd - Published: 2026-08-22 16:16 - Updated: 2026-08-25 06:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
ipv6: prevent in6_dev_get() from resurrecting inet6_dev
in6_dev_get() reads dev->ip6_ptr under RCU and then unconditionally
increments its refcount. Device teardown can clear the pointer and drop
the last reference between these operations. The increment then
resurrects an object whose RCU free has already been queued, so callers
can use it after it is freed.
Use refcount_inc_not_zero() and return NULL when the object has already
reached zero. RCU keeps the memory accessible through the attempted
reference acquisition, and a successful increment pins the object for
the caller.
An independent run on the exact unpatched 6f5156d7a31a (v7.2-rc3)
kernel reproduced the invalid reference acquisition as UID 1000:
refcount_t: addition on 0; use-after-free.
ip6_mc_source+0xef4/0x17e0
It was followed by the corresponding reference underflow in
ip6_mc_source(). The supplied trace from the same unpatched revision
additionally shows the access after the RCU read-side section ends:
BUG: KASAN: slab-use-after-free in mutex_lock+0x76/0xe0
Write of size 8 at addr ffff888015b50240 by task poc/1219
Bug found and triaged by OpenAI Security Research and
validated by Trail of Bits.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"include/net/addrconf.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "785d908f8d21c8bc78b6fb2c2932ab662bf6918a",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
},
{
"lessThan": "aedcfefdb5b7ed7f8a6196a3e68a25bdbe51d2f8",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
},
{
"lessThan": "145812b678de9f3b59780173be3c0d22ed60dd93",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
},
{
"lessThan": "cc5bd568f9b7683e60841b6fd02c10d64535bd6e",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
},
{
"lessThan": "1c206d461c680c3151daa3c89fc26eaf5bf98a7f",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
},
{
"lessThan": "680fbd7942185448eadb990a3d10a53eb946b702",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
},
{
"lessThan": "14e812ab41df0cac033479da835ec9a5de633404",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
},
{
"lessThan": "0e243671bc7b8eaf00f83dd2f4367436dc0cff98",
"status": "affected",
"version": "8814c4b533817df825485ff32ce6ac406c3a54d1",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"include/net/addrconf.h"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.19"
},
{
"lessThan": "2.6.19",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.265",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.216",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.183",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.152",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.104",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.45",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.9",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"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\nipv6: prevent in6_dev_get() from resurrecting inet6_dev\n\nin6_dev_get() reads dev-\u003eip6_ptr under RCU and then unconditionally\nincrements its refcount. Device teardown can clear the pointer and drop\nthe last reference between these operations. The increment then\nresurrects an object whose RCU free has already been queued, so callers\ncan use it after it is freed.\n\nUse refcount_inc_not_zero() and return NULL when the object has already\nreached zero. RCU keeps the memory accessible through the attempted\nreference acquisition, and a successful increment pins the object for\nthe caller.\n\nAn independent run on the exact unpatched 6f5156d7a31a (v7.2-rc3)\nkernel reproduced the invalid reference acquisition as UID 1000:\n\n refcount_t: addition on 0; use-after-free.\n ip6_mc_source+0xef4/0x17e0\n\nIt was followed by the corresponding reference underflow in\nip6_mc_source(). The supplied trace from the same unpatched revision\nadditionally shows the access after the RCU read-side section ends:\n\n BUG: KASAN: slab-use-after-free in mutex_lock+0x76/0xe0\n Write of size 8 at addr ffff888015b50240 by task poc/1219\n\nBug found and triaged by OpenAI Security Research and\nvalidated by Trail of Bits."
}
],
"id": "CVE-2026-74630",
"lastModified": "2026-08-25T06:18:41.893",
"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": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-08-22T16:16:35.943",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0e243671bc7b8eaf00f83dd2f4367436dc0cff98"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/145812b678de9f3b59780173be3c0d22ed60dd93"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/14e812ab41df0cac033479da835ec9a5de633404"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1c206d461c680c3151daa3c89fc26eaf5bf98a7f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/680fbd7942185448eadb990a3d10a53eb946b702"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/785d908f8d21c8bc78b6fb2c2932ab662bf6918a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/aedcfefdb5b7ed7f8a6196a3e68a25bdbe51d2f8"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/cc5bd568f9b7683e60841b6fd02c10d64535bd6e"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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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.
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.
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