CVE-2026-68290 (GCVE-0-2026-68290)
Vulnerability from cvelistv5
Published
2026-08-10 12:02
Modified
2026-08-17 05:02
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
rds: tcp: unregister sysctl before tearing down listen socket
rds_tcp_exit_net() frees the per-netns RDS TCP listen socket via
rds_tcp_kill_sock() before unregistering the per-netns sysctl table. Since
rds_tcp_skbuf_handler() derives the netns from
rtn->rds_tcp_listen_sock->sk, a concurrent sysctl write can race with
netns teardown and dereference the freed socket/sk.
KASAN reports the race as:
BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0
rds_tcp_skbuf_handler net/rds/tcp.c:721
proc_sys_call_handler fs/proc/proc_sysctl.c
vfs_write fs/read_write.c
__x64_sys_pwrite64 fs/read_write.c
Fix this by unregistering the RDS TCP sysctl table before calling
rds_tcp_kill_sock(). unregister_net_sysctl_table() prevents new sysctl
handlers from starting and waits for in-flight handlers to finish, so
the listen socket can then be released safely. The fix was tested
against the linked reproducer.
References
| URL | Tags | |
|---|---|---|
Impacted products
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/rds/tcp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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},
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"versionType": "git"
},
{
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"version": "7f5611cbc4871c7fb1ad36c2e5a9edad63dca95c",
"versionType": "git"
},
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"status": "affected",
"version": "6.12.10",
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}
]
},
{
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"product": "Linux",
"programFiles": [
"net/rds/tcp.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "6.13"
},
{
"lessThan": "6.13",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.101",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.42",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.6",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.2",
"versionType": "original_commit_for_fix"
}
]
}
],
"cpeApplicability": [
{
"nodes": [
{
"cpeMatch": [
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.101",
"versionStartIncluding": "6.12.10",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
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"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrds: tcp: unregister sysctl before tearing down listen socket\n\nrds_tcp_exit_net() frees the per-netns RDS TCP listen socket via\nrds_tcp_kill_sock() before unregistering the per-netns sysctl table. Since\nrds_tcp_skbuf_handler() derives the netns from\nrtn-\u003erds_tcp_listen_sock-\u003esk, a concurrent sysctl write can race with\nnetns teardown and dereference the freed socket/sk.\n\nKASAN reports the race as:\n\n BUG: KASAN: slab-use-after-free in rds_tcp_skbuf_handler+0x2aa/0x2e0\n rds_tcp_skbuf_handler net/rds/tcp.c:721\n proc_sys_call_handler fs/proc/proc_sysctl.c\n vfs_write fs/read_write.c\n __x64_sys_pwrite64 fs/read_write.c\n\nFix this by unregistering the RDS TCP sysctl table before calling\nrds_tcp_kill_sock(). unregister_net_sysctl_table() prevents new sysctl\nhandlers from starting and waits for in-flight handlers to finish, so\nthe listen socket can then be released safely. The fix was tested\nagainst the linked reproducer."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.8,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:L - The vulnerability is triggered by a local write() /pwrite64() to the per-netns sysctl file /proc/sys/net/rds/tcp/rds_tcp_{snd,rcv}buf racing with network namespace teardown; no network traffic reaches the vulnerable handler, so local syscall access is required.\nAC:L - Although this is a race, the attacker controls both sides: they create the netns, keep the sysctl fd open, choose when the netns is destroyed, and issue the concurrent sysctl write in a tight loop, so the race can be retried indefinitely until won.\nPR:L - Only an unprivileged local account is needed: unshare -Urn yields CAP_NET_ADMIN over the new netns\u0027s user_ns, and net_ctl_permissions()/net_ctl_set_ownership() then grant that user write access to the RDS TCP sysctls, while the rds_tcp module is autoloaded by an unprivileged AF_RDS socket.\nUI:N - The attacker performs every step itself \u2014 namespace creation, opening the sysctl file, triggering teardown and writing \u2014 with no action required from any other user or administrator.\nS:U - The use-after-free occurs on kernel slab objects belonging to the same kernel security authority; there is no crossing of a VM, IOMMU or other security boundary.\nC:H - The handler reads the freed listen socket and then dereferences lsock-\u003esk and sock_net(sk); by spraying the freed socket/sk slabs the attacker can steer these dereferences to chosen addresses, turning the use-after-free read into a kernel memory disclosure primitive.\nI:H - Reallocating the freed struct socket/sk with attacker-controlled data lets the attacker supply a bogus struct net pointer that drives rds_tcp_sysctl_reset()/rds_conn_path_drop() over the global RDS connection list, corrupting kernel state and giving the usual UAF path toward control-flow hijack.\nA:H - The confirmed KASAN slab-use-after-free on the freed listen socket readily oopses or panics the kernel, and the race can be repeated by an unprivileged user until it hits, giving a reliable denial of service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:02:25.806Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/80fffed08dc1c10e971066941d2daa56253f1552"
},
{
"url": "https://git.kernel.org/stable/c/16df2d154ec82e2f7e7585b4fa154751ba37729a"
},
{
"url": "https://git.kernel.org/stable/c/3aa13fe0c1bb7bc5312f878e61523e5d8cf3f85d"
},
{
"url": "https://git.kernel.org/stable/c/167e54c703ccd4fa028feb568b0d1002020cff86"
}
],
"title": "rds: tcp: unregister sysctl before tearing down listen socket",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68290",
"datePublished": "2026-08-10T12:02:23.425Z",
"dateReserved": "2026-07-30T09:28:09.380Z",
"dateUpdated": "2026-08-17T05:02:25.806Z",
"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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