FKIE_CVE-2026-98276
Vulnerability from fkie_nvd - Published: 2026-10-06 09:18 - Updated: 2026-10-07 07:17
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: lock the socket in sock_gettstamp()
sk->sk_flags must only be changed while holding the socket lock,
because sock_set_flag() and sock_reset_flag() use non atomic
operations (__set_bit() and __clear_bit()).
sock_gettstamp() is one of the last places where a bit of sk->sk_flags
is changed from a syscall without owning the socket lock, through
sock_enable_timestamp(sk, SOCK_TIMESTAMP).
sk_set_memalloc() and sk_clear_memalloc() also change sk->sk_flags
without the socket lock, but their callers (nbd, iscsi_tcp, nvme-tcp,
sunrpc, wireguard) need a careful audit, this will be addressed in a
separate patch.
Jungwoo Lee and Wongi Lee reported an UDP socket use-after-free
caused by this bug: a SIOCGSTAMPNS_NEW ioctl racing with bind()
can cancel the SOCK_RCU_FREE bit that udp_lib_get_port() just set,
because both threads perform a read-modify-write on the same word.
CPU 0 (bind) CPU 1 (SIOCGSTAMPNS_NEW)
-------------------------------- ----------------------------
read sk_flags = F read sk_flags = F
compute F | BIT(SOCK_RCU_FREE) compute F | BIT(SOCK_TIMESTAMP)
store F | BIT(SOCK_RCU_FREE)
sk_add_node_rcu(sk, ...)
store F | BIT(SOCK_TIMESTAMP)
After the lost update, SOCK_RCU_FREE is clear while the socket is
visible to lockless UDP receive lookups. sk_destruct() then frees
the socket immediately instead of waiting for a RCU grace period,
while the receive path still holds a reference-less pointer to it:
BUG: KASAN: slab-use-after-free in ipv4_pktinfo_prepare+0x30/0x410
Read of size 8 at addr ffff888008806610 by task exploit/207
CPU: 0 UID: 1000 PID: 207 Comm: exploit Not tainted 6.12.95+ #1
ipv4_pktinfo_prepare+0x30/0x410
udp_queue_rcv_one_skb+0x51c/0x1180
udp_unicast_rcv_skb+0x109/0x350
ip_protocol_deliver_rcu+0x14b/0x310
ip_local_deliver_finish+0x29d/0x390
ip_local_deliver+0x24d/0x2a0
Only grab the socket lock when SOCK_TIMESTAMP has to be set,
to keep the common case lockless.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/core/sock.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "18899e2e4023369a8f7739c2255a59a9748d8d17",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "88c804847dd87dc613b771b392ccecdb94725032",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "3b12d3967e96f1b7b977d9fc352ae29a1b299a82",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "1f73253add8365d0dad0a4f421acaa8c21d20cef",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "d9f96bc2d822501f84d1caa6275a2c6b316ca2c4",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "899650bbf985b7bfd2a7b808357df9b16e6d6959",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
},
{
"lessThan": "9ed55f3dbef4f4adfe65eb03b0c35c53229a8490",
"status": "affected",
"version": "1da177e4c3f41524e886b7f1b8a0c1fc7321cac2",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/core/sock.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "2.6.12"
},
{
"lessThan": "2.6.12",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.271",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.222",
"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-rc4",
"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: lock the socket in sock_gettstamp()\n\nsk-\u003esk_flags must only be changed while holding the socket lock,\nbecause sock_set_flag() and sock_reset_flag() use non atomic\noperations (__set_bit() and __clear_bit()).\n\nsock_gettstamp() is one of the last places where a bit of sk-\u003esk_flags\nis changed from a syscall without owning the socket lock, through\nsock_enable_timestamp(sk, SOCK_TIMESTAMP).\n\nsk_set_memalloc() and sk_clear_memalloc() also change sk-\u003esk_flags\nwithout the socket lock, but their callers (nbd, iscsi_tcp, nvme-tcp,\nsunrpc, wireguard) need a careful audit, this will be addressed in a\nseparate patch.\n\nJungwoo Lee and Wongi Lee reported an UDP socket use-after-free\ncaused by this bug: a SIOCGSTAMPNS_NEW ioctl racing with bind()\ncan cancel the SOCK_RCU_FREE bit that udp_lib_get_port() just set,\nbecause both threads perform a read-modify-write on the same word.\n\n CPU 0 (bind) CPU 1 (SIOCGSTAMPNS_NEW)\n -------------------------------- ----------------------------\n read sk_flags = F read sk_flags = F\n compute F | BIT(SOCK_RCU_FREE) compute F | BIT(SOCK_TIMESTAMP)\n store F | BIT(SOCK_RCU_FREE)\n sk_add_node_rcu(sk, ...)\n store F | BIT(SOCK_TIMESTAMP)\n\nAfter the lost update, SOCK_RCU_FREE is clear while the socket is\nvisible to lockless UDP receive lookups. sk_destruct() then frees\nthe socket immediately instead of waiting for a RCU grace period,\nwhile the receive path still holds a reference-less pointer to it:\n\n BUG: KASAN: slab-use-after-free in ipv4_pktinfo_prepare+0x30/0x410\n Read of size 8 at addr ffff888008806610 by task exploit/207\n CPU: 0 UID: 1000 PID: 207 Comm: exploit Not tainted 6.12.95+ #1\n ipv4_pktinfo_prepare+0x30/0x410\n udp_queue_rcv_one_skb+0x51c/0x1180\n udp_unicast_rcv_skb+0x109/0x350\n ip_protocol_deliver_rcu+0x14b/0x310\n ip_local_deliver_finish+0x29d/0x390\n ip_local_deliver+0x24d/0x2a0\n\nOnly grab the socket lock when SOCK_TIMESTAMP has to be set,\nto keep the common case lockless."
}
],
"id": "CVE-2026-98276",
"lastModified": "2026-10-07T07:17:07.640",
"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": "2026-10-06T09:18:17.360",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/17b2a1eb97fdb2a2cbaeab3b146b26797ea9311f"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/18899e2e4023369a8f7739c2255a59a9748d8d17"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/1f73253add8365d0dad0a4f421acaa8c21d20cef"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/3b12d3967e96f1b7b977d9fc352ae29a1b299a82"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/88c804847dd87dc613b771b392ccecdb94725032"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/899650bbf985b7bfd2a7b808357df9b16e6d6959"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9ed55f3dbef4f4adfe65eb03b0c35c53229a8490"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/d9f96bc2d822501f84d1caa6275a2c6b316ca2c4"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
Loading…
Loading…
Drag nodes to arrange them. Double-click a related vulnerability to open it, or a source to visit its link. The Physics button on the left tunes the layout and the simulation; the legend at the bottom left hides or shows nodes by kind and by sighting type.
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.
Vulnerability timeline
Sightings and recorded dates, grouped by day · UTC
Loading timeline…
Loading…
Loading…
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.
Loading…
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.