CVE-2026-68335 (GCVE-0-2026-68335)
Vulnerability from cvelistv5
Published
2026-08-10 12:03
Modified
2026-08-19 16:33
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
rds: drop incoming messages that cross network namespace boundaries
rds_find_bound() looks up the destination socket using a global
rhashtable keyed solely on (addr, port, scope_id). Network namespaces
are not part of the key, so a sender in netns A can deliver an incoming
message (inc) to a socket that lives in a different netns B.
When this happens, inc->i_conn points to an rds_connection whose c_net
is netns A, but the receiving rs lives in netns B. Once the child
process that created netns A exits, cleanup_net() calls
rds_loop_exit_net() -> rds_loop_kill_conns() -> rds_conn_destroy(),
freeing that connection. If the survivor socket in netns B still holds
the inc, any subsequent dereference of inc->i_conn is a use-after-free.
There are two dangerous sites in rds_clear_recv_queue():
1. inc->i_conn->c_lcong (offset 88 of freed rds_connection, size 200)
read via rds_recv_rcvbuf_delta() -- confirmed by KASAN.
2. inc->i_conn->c_trans->inc_free(inc) (function pointer at offset 80)
called via rds_inc_put() when the inc refcount reaches zero -- same
race window, potential call-through-freed-object primitive.
The bug is reachable from unprivileged user namespaces
(CLONE_NEWUSER + CLONE_NEWNET), available since Linux 3.8.
Fix this by rejecting the delivery in rds_recv_incoming() when the
socket returned by rds_find_bound() belongs to a different network
namespace than the connection that carried the message. Use the
existing rds_conn_net() / sock_net() helpers and net_eq() for the
comparison.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c809195f5523dd4d09403bbb1c9732d548aa0d1e Version: c827073c95fde388bc65fe5227f944eaf859b9f0 Version: 4.17.19 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/rds/recv.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "742ff6f02545212e991cd8b45011e40d2c2ef25a",
"status": "affected",
"version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
"versionType": "git"
},
{
"lessThan": "abff41fd928328bbf3dda1140beb2e61fa424ccd",
"status": "affected",
"version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
"versionType": "git"
},
{
"lessThan": "03c574112e5d066df0ddce36d7438e850bcf3050",
"status": "affected",
"version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
"versionType": "git"
},
{
"lessThan": "1e2e2d9806944fe485824d617c8b7c78116c22db",
"status": "affected",
"version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
"versionType": "git"
},
{
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"status": "affected",
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},
{
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"status": "affected",
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},
{
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"status": "affected",
"version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
"versionType": "git"
},
{
"lessThan": "5521ae71e32a8069ed4ca6e792179dc57bc43ab2",
"status": "affected",
"version": "c809195f5523dd4d09403bbb1c9732d548aa0d1e",
"versionType": "git"
},
{
"status": "affected",
"version": "c827073c95fde388bc65fe5227f944eaf859b9f0",
"versionType": "git"
},
{
"lessThan": "4.18",
"status": "affected",
"version": "4.17.19",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/rds/recv.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "4.18"
},
{
"lessThan": "4.18",
"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": "6.6.148",
"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": "5.10.265",
"versionStartIncluding": "4.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "5.15.216",
"versionStartIncluding": "4.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.1.183",
"versionStartIncluding": "4.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.6.148",
"versionStartIncluding": "4.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.12.101",
"versionStartIncluding": "4.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "6.18.42",
"versionStartIncluding": "4.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.1.6",
"versionStartIncluding": "4.18",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionEndExcluding": "7.2",
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"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "4.17.19",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nrds: drop incoming messages that cross network namespace boundaries\n\nrds_find_bound() looks up the destination socket using a global\nrhashtable keyed solely on (addr, port, scope_id). Network namespaces\nare not part of the key, so a sender in netns A can deliver an incoming\nmessage (inc) to a socket that lives in a different netns B.\n\nWhen this happens, inc-\u003ei_conn points to an rds_connection whose c_net\nis netns A, but the receiving rs lives in netns B. Once the child\nprocess that created netns A exits, cleanup_net() calls\nrds_loop_exit_net() -\u003e rds_loop_kill_conns() -\u003e rds_conn_destroy(),\nfreeing that connection. If the survivor socket in netns B still holds\nthe inc, any subsequent dereference of inc-\u003ei_conn is a use-after-free.\n\nThere are two dangerous sites in rds_clear_recv_queue():\n 1. inc-\u003ei_conn-\u003ec_lcong (offset 88 of freed rds_connection, size 200)\n read via rds_recv_rcvbuf_delta() -- confirmed by KASAN.\n 2. inc-\u003ei_conn-\u003ec_trans-\u003einc_free(inc) (function pointer at offset 80)\n called via rds_inc_put() when the inc refcount reaches zero -- same\n race window, potential call-through-freed-object primitive.\n\nThe bug is reachable from unprivileged user namespaces\n(CLONE_NEWUSER + CLONE_NEWNET), available since Linux 3.8.\n\nFix this by rejecting the delivery in rds_recv_incoming() when the\nsocket returned by rds_find_bound() belongs to a different network\nnamespace than the connection that carried the message. Use the\nexisting rds_conn_net() / sock_net() helpers and net_eq() for the\ncomparison."
}
],
"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 - Exploitation requires local syscall access: the attacker must create RDS sockets and a network namespace (CLONE_NEWUSER|CLONE_NEWNET), then trigger namespace teardown to free the connection. A remote RDS peer cannot drive the netns-destruction half of the sequence, so the vulnerability is reachable only locally.\nAC:L - The attacker controls the entire sequence deterministically \u2014 bind a socket in one netns, send a loopback RDS message from a second netns so the inc is queued cross-netns, then exit that netns to free inc-\u003ei_conn. No race must be won and no uncontrollable precondition exists; the UAF is confirmed reproducible under KASAN.\nPR:L - Only an unprivileged local user account is required; the needed CAP_NET_ADMIN for creating and configuring the second network namespace is obtained inside a user namespace the attacker owns, as the commit explicitly notes (\"reachable from unprivileged user namespaces\").\nUI:N - The attacker performs every step \u2014 socket creation, cross-netns send, namespace teardown, and the subsequent read/close that dereferences the freed connection \u2014 with no action from any other user or administrator.\nS:U - The use-after-free corrupts kernel memory within the same kernel security authority; there is no crossing of a hypervisor, IOMMU, or comparable trust boundary.\nC:H - The stale inc-\u003ei_conn is dereferenced to read c_lcong from a freed 200-byte rds_connection, and the freed slot can be reclaimed with attacker-groomed data, giving a use-after-free read primitive usable to disclose kernel memory contents.\nI:H - rds_inc_put() calls inc-\u003ei_conn-\u003ec_trans-\u003einc_free(inc) through a function pointer at offset 80 of the freed object \u2014 an indirect call through freed memory that the commit calls a \"call-through-freed-object primitive\", which after heap reclamation is a control-flow hijack path leading to arbitrary kernel modification.\nA:H - Dereferencing the freed rds_connection in rds_clear_recv_queue() and calling through its freed transport vtable reliably corrupts kernel state and panics the machine (KASAN-confirmed use-after-free), causing a full denial of service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-19T16:33:33.100Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/742ff6f02545212e991cd8b45011e40d2c2ef25a"
},
{
"url": "https://git.kernel.org/stable/c/abff41fd928328bbf3dda1140beb2e61fa424ccd"
},
{
"url": "https://git.kernel.org/stable/c/03c574112e5d066df0ddce36d7438e850bcf3050"
},
{
"url": "https://git.kernel.org/stable/c/1e2e2d9806944fe485824d617c8b7c78116c22db"
},
{
"url": "https://git.kernel.org/stable/c/cfb3ce07b705e486e022a2f2b1242b48f13981ff"
},
{
"url": "https://git.kernel.org/stable/c/9591042533140dfe6608d9344806d567dcd39d02"
},
{
"url": "https://git.kernel.org/stable/c/0f8690e3869109cd5803ccb400889d20a0b54e0e"
},
{
"url": "https://git.kernel.org/stable/c/5521ae71e32a8069ed4ca6e792179dc57bc43ab2"
}
],
"title": "rds: drop incoming messages that cross network namespace boundaries",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-68335",
"datePublished": "2026-08-10T12:03:11.547Z",
"dateReserved": "2026-07-30T09:28:09.383Z",
"dateUpdated": "2026-08-19T16:33:33.100Z",
"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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