CVE-2026-52947 (GCVE-0-2026-52947)
Vulnerability from cvelistv5 – Published: 2026-06-24 16:26 – Updated: 2026-06-28 06:37
VLAI
Title
net: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove
In qrtr_port_remove(), the socket reference count is decremented via
__sock_put() before the port is removed from the qrtr_ports XArray and
before the RCU grace period elapses.
This breaks the fundamental RCU update paradigm. It exposes a race
window where a concurrent RCU reader (such as qrtr_reset_ports() or
qrtr_port_lookup()) can obtain a pointer to the socket from the XArray,
and attempt to call sock_hold() on a socket whose reference count has
already dropped to zero.
This exact race condition was hit during syzkaller fuzzing, leading to
the following refcount saturation warning and a potential Use-After-Free:
refcount_t: saturated; leaking memory.
WARNING: CPU: 3 PID: 1273 at lib/refcount.c:22 refcount_warn_saturate+0xae/0x1d0
Modules linked in: qrtr(+) bochs drm_shmem_helper ...
Call Trace:
<TASK>
qrtr_reset_ports net/qrtr/af_qrtr.c:768 [inline] [qrtr]
__qrtr_bind.isra.0+0x48b/0x570 net/qrtr/af_qrtr.c:805 [qrtr]
qrtr_bind+0x17d/0x210 net/qrtr/af_qrtr.c:901 [qrtr]
kernel_bind+0xe4/0x120 net/socket.c:3592
qrtr_ns_init+0x1a6/0x380 net/qrtr/ns.c:715 [qrtr]
qrtr_proto_init+0x3b/0xff0 net/qrtr/af_qrtr.c:169 [qrtr]
do_one_initcall+0xf5/0x5e0 init/main.c:1283
...
</TASK>
Fix this by deferring the reference count decrement until after the
xa_erase() and the synchronize_rcu() complete.
(Note: The v1 of this patch incorrectly replaced __sock_put() with
sock_put(). As Simon Horman pointed out, the callers of qrtr_port_remove()
still hold a reference to the socket, so freeing the socket memory here
would lead to a subsequent UAF in the caller. Thus, the __sock_put() is
kept, but only repositioned to close the RCU race.)
Severity
7.8 (High)
Assigner
References
8 references
Impacted products
2 products
| Vendor | Product | Version | |
|---|---|---|---|
| Linux | Linux |
Affected:
bdabad3e363d825ddf9679dd431cca0b2c30f881 , < 2aa4c12723fe432e623462a3be42a197a128722b
(git)
Affected: bdabad3e363d825ddf9679dd431cca0b2c30f881 , < 03bfa95e452e2b6ccd76a332060ae4feaf5ad84d (git) Affected: bdabad3e363d825ddf9679dd431cca0b2c30f881 , < 474293d90880622fde9d2430fb0165767090f7b3 (git) Affected: bdabad3e363d825ddf9679dd431cca0b2c30f881 , < 2047c2aa0963bb2872fd722300a15bcb441a4c00 (git) Affected: bdabad3e363d825ddf9679dd431cca0b2c30f881 , < 7de2d447072be3b1a76793f034432338fc9c494b (git) Affected: bdabad3e363d825ddf9679dd431cca0b2c30f881 , < ab269990ed58143a92a263be1bee626d82ac03da (git) Affected: bdabad3e363d825ddf9679dd431cca0b2c30f881 , < 3b20ec8f31e8a6a6782243f473b0abd3463621df (git) Affected: bdabad3e363d825ddf9679dd431cca0b2c30f881 , < a2171131ecda1ed61a594a1eb715e75fdad0fef5 (git) |
|
| Linux | Linux |
Affected:
4.7
Unaffected: 0 , < 4.7 (semver) Unaffected: 5.10.259 , ≤ 5.10.* (semver) Unaffected: 5.15.210 , ≤ 5.15.* (semver) Unaffected: 6.1.176 , ≤ 6.1.* (semver) Unaffected: 6.6.143 , ≤ 6.6.* (semver) Unaffected: 6.12.94 , ≤ 6.12.* (semver) Unaffected: 6.18.36 , ≤ 6.18.* (semver) Unaffected: 7.0.13 , ≤ 7.0.* (semver) Unaffected: 7.1 , ≤ * (original_commit_for_fix) |
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"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove\n\nIn qrtr_port_remove(), the socket reference count is decremented via\n__sock_put() before the port is removed from the qrtr_ports XArray and\nbefore the RCU grace period elapses.\n\nThis breaks the fundamental RCU update paradigm. It exposes a race\nwindow where a concurrent RCU reader (such as qrtr_reset_ports() or\nqrtr_port_lookup()) can obtain a pointer to the socket from the XArray,\nand attempt to call sock_hold() on a socket whose reference count has\nalready dropped to zero.\n\nThis exact race condition was hit during syzkaller fuzzing, leading to\nthe following refcount saturation warning and a potential Use-After-Free:\n\n refcount_t: saturated; leaking memory.\n WARNING: CPU: 3 PID: 1273 at lib/refcount.c:22 refcount_warn_saturate+0xae/0x1d0\n Modules linked in: qrtr(+) bochs drm_shmem_helper ...\n Call Trace:\n \u003cTASK\u003e\n qrtr_reset_ports net/qrtr/af_qrtr.c:768 [inline] [qrtr]\n __qrtr_bind.isra.0+0x48b/0x570 net/qrtr/af_qrtr.c:805 [qrtr]\n qrtr_bind+0x17d/0x210 net/qrtr/af_qrtr.c:901 [qrtr]\n kernel_bind+0xe4/0x120 net/socket.c:3592\n qrtr_ns_init+0x1a6/0x380 net/qrtr/ns.c:715 [qrtr]\n qrtr_proto_init+0x3b/0xff0 net/qrtr/af_qrtr.c:169 [qrtr]\n do_one_initcall+0xf5/0x5e0 init/main.c:1283\n ...\n \u003c/TASK\u003e\n\nFix this by deferring the reference count decrement until after the\nxa_erase() and the synchronize_rcu() complete.\n\n(Note: The v1 of this patch incorrectly replaced __sock_put() with\nsock_put(). As Simon Horman pointed out, the callers of qrtr_port_remove()\nstill hold a reference to the socket, so freeing the socket memory here\nwould lead to a subsequent UAF in the caller. Thus, the __sock_put() is\nkept, but only repositioned to close the RCU race.)"
}
],
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"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"
}
}
],
"providerMetadata": {
"dateUpdated": "2026-06-28T06:37:05.590Z",
"orgId": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"shortName": "Linux"
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"references": [
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"url": "https://git.kernel.org/stable/c/2aa4c12723fe432e623462a3be42a197a128722b"
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"url": "https://git.kernel.org/stable/c/03bfa95e452e2b6ccd76a332060ae4feaf5ad84d"
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{
"url": "https://git.kernel.org/stable/c/2047c2aa0963bb2872fd722300a15bcb441a4c00"
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"url": "https://git.kernel.org/stable/c/7de2d447072be3b1a76793f034432338fc9c494b"
},
{
"url": "https://git.kernel.org/stable/c/ab269990ed58143a92a263be1bee626d82ac03da"
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"url": "https://git.kernel.org/stable/c/3b20ec8f31e8a6a6782243f473b0abd3463621df"
},
{
"url": "https://git.kernel.org/stable/c/a2171131ecda1ed61a594a1eb715e75fdad0fef5"
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"title": "net: qrtr: fix refcount saturation and potential UAF in qrtr_port_remove",
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"cveId": "CVE-2026-52947",
"datePublished": "2026-06-24T16:26:05.062Z",
"dateReserved": "2026-06-09T07:44:35.371Z",
"dateUpdated": "2026-06-28T06:37:05.590Z",
"state": "PUBLISHED"
},
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"date": "2026-06-30",
"epss": "0.00135",
"percentile": "0.03288"
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It exposes a race\\nwindow where a concurrent RCU reader (such as qrtr_reset_ports() or\\nqrtr_port_lookup()) can obtain a pointer to the socket from the XArray,\\nand attempt to call sock_hold() on a socket whose reference count has\\nalready dropped to zero.\\n\\nThis exact race condition was hit during syzkaller fuzzing, leading to\\nthe following refcount saturation warning and a potential Use-After-Free:\\n\\n refcount_t: saturated; leaking memory.\\n WARNING: CPU: 3 PID: 1273 at lib/refcount.c:22 refcount_warn_saturate+0xae/0x1d0\\n Modules linked in: qrtr(+) bochs drm_shmem_helper ...\\n Call Trace:\\n \u003cTASK\u003e\\n qrtr_reset_ports net/qrtr/af_qrtr.c:768 [inline] [qrtr]\\n __qrtr_bind.isra.0+0x48b/0x570 net/qrtr/af_qrtr.c:805 [qrtr]\\n qrtr_bind+0x17d/0x210 net/qrtr/af_qrtr.c:901 [qrtr]\\n kernel_bind+0xe4/0x120 net/socket.c:3592\\n qrtr_ns_init+0x1a6/0x380 net/qrtr/ns.c:715 [qrtr]\\n qrtr_proto_init+0x3b/0xff0 net/qrtr/af_qrtr.c:169 [qrtr]\\n do_one_initcall+0xf5/0x5e0 init/main.c:1283\\n ...\\n \u003c/TASK\u003e\\n\\nFix this by deferring the reference count decrement until after the\\nxa_erase() and the synchronize_rcu() complete.\\n\\n(Note: The v1 of this patch incorrectly replaced __sock_put() with\\nsock_put(). As Simon Horman pointed out, the callers of qrtr_port_remove()\\nstill hold a reference to the socket, so freeing the socket memory here\\nwould lead to a subsequent UAF in the caller. Thus, the __sock_put() is\\nkept, but only repositioned to close the RCU race.)\"}],\"affected\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"affectedData\":[{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"unaffected\",\"programFiles\":[\"net/qrtr/af_qrtr.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"2aa4c12723fe432e623462a3be42a197a128722b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"03bfa95e452e2b6ccd76a332060ae4feaf5ad84d\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"474293d90880622fde9d2430fb0165767090f7b3\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"2047c2aa0963bb2872fd722300a15bcb441a4c00\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"7de2d447072be3b1a76793f034432338fc9c494b\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"ab269990ed58143a92a263be1bee626d82ac03da\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"3b20ec8f31e8a6a6782243f473b0abd3463621df\",\"versionType\":\"git\",\"status\":\"affected\"},{\"version\":\"bdabad3e363d825ddf9679dd431cca0b2c30f881\",\"lessThan\":\"a2171131ecda1ed61a594a1eb715e75fdad0fef5\",\"versionType\":\"git\",\"status\":\"affected\"}]},{\"vendor\":\"Linux\",\"product\":\"Linux\",\"defaultStatus\":\"affected\",\"programFiles\":[\"net/qrtr/af_qrtr.c\"],\"repo\":\"https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git\",\"versions\":[{\"version\":\"4.7\",\"status\":\"affected\"},{\"version\":\"0\",\"lessThan\":\"4.7\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.10.259\",\"lessThanOrEqual\":\"5.10.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"5.15.210\",\"lessThanOrEqual\":\"5.15.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.1.176\",\"lessThanOrEqual\":\"6.1.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.6.143\",\"lessThanOrEqual\":\"6.6.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.12.94\",\"lessThanOrEqual\":\"6.12.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"6.18.36\",\"lessThanOrEqual\":\"6.18.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.0.13\",\"lessThanOrEqual\":\"7.0.*\",\"versionType\":\"semver\",\"status\":\"unaffected\"},{\"version\":\"7.1\",\"lessThanOrEqual\":\"*\",\"versionType\":\"original_commit_for_fix\",\"status\":\"unaffected\"}]}]}],\"metrics\":{\"cvssMetricV31\":[{\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\",\"type\":\"Secondary\",\"cvssData\":{\"version\":\"3.1\",\"vectorString\":\"CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H\",\"baseScore\":7.8,\"baseSeverity\":\"HIGH\",\"attackVector\":\"LOCAL\",\"attackComplexity\":\"LOW\",\"privilegesRequired\":\"LOW\",\"userInteraction\":\"NONE\",\"scope\":\"UNCHANGED\",\"confidentialityImpact\":\"HIGH\",\"integrityImpact\":\"HIGH\",\"availabilityImpact\":\"HIGH\"},\"exploitabilityScore\":1.8,\"impactScore\":5.9}]},\"references\":[{\"url\":\"https://git.kernel.org/stable/c/03bfa95e452e2b6ccd76a332060ae4feaf5ad84d\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2047c2aa0963bb2872fd722300a15bcb441a4c00\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/2aa4c12723fe432e623462a3be42a197a128722b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/3b20ec8f31e8a6a6782243f473b0abd3463621df\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/474293d90880622fde9d2430fb0165767090f7b3\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/7de2d447072be3b1a76793f034432338fc9c494b\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/a2171131ecda1ed61a594a1eb715e75fdad0fef5\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"},{\"url\":\"https://git.kernel.org/stable/c/ab269990ed58143a92a263be1bee626d82ac03da\",\"source\":\"416baaa9-dc9f-4396-8d5f-8c081fb06d67\"}]}}"
}
}
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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.
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