CVE-2026-72464 (GCVE-0-2026-72464)
Vulnerability from cvelistv5
Published
2026-08-15 05:57
Modified
2026-08-17 05:44
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
xprtrdma: Repost Receive buffers for malformed replies
rpcrdma_wc_receive() decrements the transport's Receive count for
every completion before it dispatches a successful Receive to
rpcrdma_reply_handler(). The handler must post a replacement
Receive WR before returning unless ownership of the rep has moved
elsewhere, as on the backchannel path.
Commit 2ae50ad68cd7 ("xprtrdma: Close window between waking RPC
senders and posting Receives") moved the Receive refill out of
rpcrdma_wc_receive(), where it had run ahead of every reply, into
rpcrdma_reply_handler() so that the responder's credit grant could
be parsed before reposting. The bad-version and short-reply exits
never reach that refill: they recycle the rep and return without
calling rpcrdma_post_recvs().
A remote peer can therefore drain the client's posted Receive
queue by sending a sustained stream of replies that are shorter
than the fixed transport header or that carry an unrecognized
RPC/RDMA version. Each such reply consumes one posted Receive
without replacing it. Once the queue empties, the peer's next
Send finds no posted Receive and the transport stalls until
reconnect.
Route both malformed-reply exits through the shared repost tail
after recycling the rep, refilling against buf->rb_credits, the
most recent accepted credit grant. Neither exit updates the
congestion window, so RPCs admitted under the previous grant
remain in flight awaiting replies. A smaller refill target would
let a stream of malformed replies ratchet the posted Receive count
down to the batch floor while the congestion window still admits
rb_credits RPCs; a burst of valid replies to those RPCs could then
overrun the posted Receives, and because the client connects with
rnr_retry_count of zero, a single RNR NAK terminates the
connection. Refilling against rb_credits also restores the target
that applied to malformed replies before commit 2ae50ad68cd7
("xprtrdma: Close window between waking RPC senders and posting
Receives") when rpcrdma_post_recvs() computed it from rb_credits
internally. rb_credits is at least one from connection
establishment onward, so the repost path always keeps Receives
posted.
References
Impacted products
| Vendor | Product | Version | ||
|---|---|---|---|---|
| Linux | Linux |
Version: 2ae50ad68cd79224198b525f7bd645c9da98b6ff Version: 2ae50ad68cd79224198b525f7bd645c9da98b6ff Version: 2ae50ad68cd79224198b525f7bd645c9da98b6ff Version: 2ae50ad68cd79224198b525f7bd645c9da98b6ff Version: 2ae50ad68cd79224198b525f7bd645c9da98b6ff Version: 2ae50ad68cd79224198b525f7bd645c9da98b6ff Version: 3791c5982ba1eebf2900ee7ca7b9a89619c26d54 Version: 5.4.13 ≤ |
||
{
"containers": {
"cna": {
"affected": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/sunrpc/xprtrdma/rpc_rdma.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "ef6fb8a5c521f1a07f85202d13e8f2898f247362",
"status": "affected",
"version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff",
"versionType": "git"
},
{
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"versionType": "git"
},
{
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"versionType": "git"
},
{
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"version": "2ae50ad68cd79224198b525f7bd645c9da98b6ff",
"versionType": "git"
},
{
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"status": "affected",
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"versionType": "git"
},
{
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"versionType": "git"
},
{
"status": "affected",
"version": "3791c5982ba1eebf2900ee7ca7b9a89619c26d54",
"versionType": "git"
},
{
"lessThan": "5.5",
"status": "affected",
"version": "5.4.13",
"versionType": "semver"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/sunrpc/xprtrdma/rpc_rdma.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
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"version": "5.5"
},
{
"lessThan": "5.5",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.178",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.145",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.97",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.40",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.1.*",
"status": "unaffected",
"version": "7.1.5",
"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": "6.1.178",
"versionStartIncluding": "5.5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"vulnerable": true
},
{
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},
{
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"versionEndExcluding": "6.18.40",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
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"versionStartIncluding": "5.5",
"vulnerable": true
},
{
"criteria": "cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:*",
"versionStartIncluding": "5.4.13",
"vulnerable": true
}
],
"negate": false,
"operator": "OR"
}
]
}
],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nxprtrdma: Repost Receive buffers for malformed replies\n\nrpcrdma_wc_receive() decrements the transport\u0027s Receive count for\nevery completion before it dispatches a successful Receive to\nrpcrdma_reply_handler(). The handler must post a replacement\nReceive WR before returning unless ownership of the rep has moved\nelsewhere, as on the backchannel path.\n\nCommit 2ae50ad68cd7 (\"xprtrdma: Close window between waking RPC\nsenders and posting Receives\") moved the Receive refill out of\nrpcrdma_wc_receive(), where it had run ahead of every reply, into\nrpcrdma_reply_handler() so that the responder\u0027s credit grant could\nbe parsed before reposting. The bad-version and short-reply exits\nnever reach that refill: they recycle the rep and return without\ncalling rpcrdma_post_recvs().\n\nA remote peer can therefore drain the client\u0027s posted Receive\nqueue by sending a sustained stream of replies that are shorter\nthan the fixed transport header or that carry an unrecognized\nRPC/RDMA version. Each such reply consumes one posted Receive\nwithout replacing it. Once the queue empties, the peer\u0027s next\nSend finds no posted Receive and the transport stalls until\nreconnect.\n\nRoute both malformed-reply exits through the shared repost tail\nafter recycling the rep, refilling against buf-\u003erb_credits, the\nmost recent accepted credit grant. Neither exit updates the\ncongestion window, so RPCs admitted under the previous grant\nremain in flight awaiting replies. A smaller refill target would\nlet a stream of malformed replies ratchet the posted Receive count\ndown to the batch floor while the congestion window still admits\nrb_credits RPCs; a burst of valid replies to those RPCs could then\noverrun the posted Receives, and because the client connects with\nrnr_retry_count of zero, a single RNR NAK terminates the\nconnection. Refilling against rb_credits also restores the target\nthat applied to malformed replies before commit 2ae50ad68cd7\n(\"xprtrdma: Close window between waking RPC senders and posting\nReceives\") when rpcrdma_post_recvs() computed it from rb_credits\ninternally. rb_credits is at least one from connection\nestablishment onward, so the repost path always keeps Receives\nposted."
}
],
"metrics": [
{
"cvssV3_1": {
"baseScore": 7.5,
"baseSeverity": "HIGH",
"vectorString": "CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H",
"version": "3.1"
},
"scenarios": [
{
"lang": "en",
"value": "AV:N - Malicious or compromised NFS/RDMA server sends malformed RPC reply messages over an established RDMA connection; the kernel client processes them in rpcrdma_wc_receive()/rpcrdma_reply_handler() without any local access.\nAC:L - Remote server reliably triggers the bug by streaming replies shorter than the fixed RPC/RDMA header or carrying an unrecognized version; each consumes a posted Receive without reposting a replacement.\nPR:N - Attacker needs no credentials on the victim host, only the ability to act as the connected RDMA peer (e.g., a malicious or compromised NFS server the client has mounted).\nUI:N - Exploitation requires only an active NFS-over-RDMA client session; no additional victim action is needed beyond an existing mount/connection used for normal I/O.\nS:U - Impact is confined to SunRPC/RDMA transport availability on the NFS client; it does not cross VM, container, or kernel/user security boundaries.\nC:N - No memory corruption or out-of-bounds access occurs; short or bad-version replies are detected during header decode and the buffer is recycled without disclosing kernel data.\nI:N - The flaw only fails to repost Receive buffers after malformed replies; it does not corrupt memory, alter RPC payloads, or enable arbitrary kernel writes.\nA:H - Sustained malformed replies drain all posted Receives, stalling the transport until reconnect; a burst of valid replies can trigger RNR NAK and disconnect (rnr_retry_count=0), denying NFS/RDMA service."
}
]
}
],
"providerMetadata": {
"dateUpdated": "2026-08-17T05:44:30.706Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
},
"references": [
{
"url": "https://git.kernel.org/stable/c/ef6fb8a5c521f1a07f85202d13e8f2898f247362"
},
{
"url": "https://git.kernel.org/stable/c/4322fd9645ee769ad29ce5caea74a1cd9b17269d"
},
{
"url": "https://git.kernel.org/stable/c/19fae02b272ee4bcdfb5db57f402d28f1697167a"
},
{
"url": "https://git.kernel.org/stable/c/007b4da2f38dcc16a13265416f4ca9f179bab610"
},
{
"url": "https://git.kernel.org/stable/c/d7c531ab477ae94fd03771d707fd29c787408039"
},
{
"url": "https://git.kernel.org/stable/c/abc011ddaf1617e3e82d8a1e87daa7ddbfb9bac5"
}
],
"title": "xprtrdma: Repost Receive buffers for malformed replies",
"x_generator": {
"engine": "bippy-1.2.0"
}
}
},
"cveMetadata": {
"assignerOrgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"assignerShortName": "Linux",
"cveId": "CVE-2026-72464",
"datePublished": "2026-08-15T05:57:08.080Z",
"dateReserved": "2026-08-09T03:40:39.933Z",
"dateUpdated": "2026-08-17T05:44:30.706Z",
"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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