CVE-2026-99138 (GCVE-0-2026-99138)
Vulnerability from cvelistv5
Published
2026-10-28 10:34
Modified
2026-10-28 10:34
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)
do_tcp_getsockopt() reads icsk->icsk_ca_ops and dereferences the
get_info function pointer without rcu_read_lock(). With BPF struct_ops
congestion control, ca_ops can point to dynamically allocated memory
that is freed concurrently, resulting in a use-after-free when the
kernel dereferences or calls through the stale pointer.
BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0
Read of size 8 at addr ffff888013701258 by task exploit/149
do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564)
tcp_getsockopt+0x91/0xf0
__sys_getsockopt+0xf7/0x170
Fix this by wrapping the ca_ops load and get_info call within
rcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load
the icsk_ca_ops pointer.
References
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/ipv4/tcp.c",
"net/ipv4/tcp_dctcp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "86814e5370068ec2bf0caa6e6d55c3e5bfc6c324",
"status": "affected",
"version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
"versionType": "git"
},
{
"lessThan": "39aa489e85752f9de214edb0f85e4d578e57af29",
"status": "affected",
"version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
"versionType": "git"
},
{
"lessThan": "385e474086c2e7e29e2dded690be40dc273e20ee",
"status": "affected",
"version": "0baf26b0fcd74bbfcef53c5d5e8bad2b99c8d0d2",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/ipv4/tcp.c",
"net/ipv4/tcp_dctcp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "5.6"
},
{
"lessThan": "5.6",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.59",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.13",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.59",
"versionStartIncluding": "5.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2.13",
"versionStartIncluding": "5.6",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.3",
"versionStartIncluding": "5.6",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\ntcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)\n\ndo_tcp_getsockopt() reads icsk-\u003eicsk_ca_ops and dereferences the\nget_info function pointer without rcu_read_lock(). With BPF struct_ops\ncongestion control, ca_ops can point to dynamically allocated memory\nthat is freed concurrently, resulting in a use-after-free when the\nkernel dereferences or calls through the stale pointer.\n\n BUG: KASAN: slab-use-after-free in do_tcp_getsockopt+0x2037/0x23e0\n Read of size 8 at addr ffff888013701258 by task exploit/149\n do_tcp_getsockopt+0x2037/0x23e0 (net/ipv4/tcp.c:4564)\n tcp_getsockopt+0x91/0xf0\n __sys_getsockopt+0xf7/0x170\n\nFix this by wrapping the ca_ops load and get_info call within\nrcu_read_lock()/rcu_read_unlock(), and using READ_ONCE() to load\nthe icsk_ca_ops pointer."
}
],
"providerMetadata": {
"dateUpdated": "2026-10-28T10:34:49.993Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/86814e5370068ec2bf0caa6e6d55c3e5bfc6c324"
},
{
"url": "https://git.kernel.org/stable/c/39aa489e85752f9de214edb0f85e4d578e57af29"
},
{
"url": "https://git.kernel.org/stable/c/385e474086c2e7e29e2dded690be40dc273e20ee"
}
],
"title": "tcp: fix use-after-free in do_tcp_getsockopt(TCP_CC_INFO)",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-99138",
"datePublished": "2026-10-28T10:34:49.993Z",
"dateReserved": "2026-09-25T10:25:14.395Z",
"dateUpdated": "2026-10-28T10:34:49.993Z",
"state": "PUBLISHED"
},
"dataType": "CVE_RECORD",
"dataVersion": "5.2"
}
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Sightings
| Author | Source | Type | Date |
|---|
Nomenclature
- Seen: The vulnerability was mentioned, discussed, or seen somewhere by the user.
- Confirmed: The vulnerability is confirmed from an analyst perspective.
- Published Proof of Concept: A public proof of concept is available for this vulnerability.
- Exploited: This vulnerability was exploited and seen by the user reporting the sighting.
- Patched: This vulnerability was successfully patched by the user reporting the sighting.
- Not exploited: This vulnerability was not exploited or seen by the user reporting the sighting.
- Not confirmed: The user expresses doubt about the veracity of the vulnerability.
- Not patched: This vulnerability was not successfully patched by the user reporting the sighting.
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