CVE-2026-23255 (GCVE-0-2026-23255)
Vulnerability from cvelistv5
Published
2026-03-18 17:41
Modified
2026-04-27 13:56
Severity ?
VLAI Severity ?
EPSS score ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: add proper RCU protection to /proc/net/ptype
Yin Fengwei reported an RCU stall in ptype_seq_show() and provided
a patch.
Real issue is that ptype_seq_next() and ptype_seq_show() violate
RCU rules.
ptype_seq_show() runs under rcu_read_lock(), and reads pt->dev
to get device name without any barrier.
At the same time, concurrent writers can remove a packet_type structure
(which is correctly freed after an RCU grace period) and clear pt->dev
without an RCU grace period.
Define ptype_iter_state to carry a dev pointer along seq_net_private:
struct ptype_iter_state {
struct seq_net_private p;
struct net_device *dev; // added in this patch
};
We need to record the device pointer in ptype_get_idx() and
ptype_seq_next() so that ptype_seq_show() is safe against
concurrent pt->dev changes.
We also need to add full RCU protection in ptype_seq_next().
(Missing READ_ONCE() when reading list.next values)
Many thanks to Dong Chenchen for providing a repro.
References
| URL | Tags | |
|---|---|---|
Impacted products
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"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: add proper RCU protection to /proc/net/ptype\n\nYin Fengwei reported an RCU stall in ptype_seq_show() and provided\na patch.\n\nReal issue is that ptype_seq_next() and ptype_seq_show() violate\nRCU rules.\n\nptype_seq_show() runs under rcu_read_lock(), and reads pt-\u003edev\nto get device name without any barrier.\n\nAt the same time, concurrent writers can remove a packet_type structure\n(which is correctly freed after an RCU grace period) and clear pt-\u003edev\nwithout an RCU grace period.\n\nDefine ptype_iter_state to carry a dev pointer along seq_net_private:\n\nstruct ptype_iter_state {\n\tstruct seq_net_private\tp;\n\tstruct net_device\t*dev; // added in this patch\n};\n\nWe need to record the device pointer in ptype_get_idx() and\nptype_seq_next() so that ptype_seq_show() is safe against\nconcurrent pt-\u003edev changes.\n\nWe also need to add full RCU protection in ptype_seq_next().\n(Missing READ_ONCE() when reading list.next values)\n\nMany thanks to Dong Chenchen for providing a repro."
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"datePublished": "2026-03-18T17:41:01.445Z",
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"dateUpdated": "2026-04-27T13:56:09.657Z",
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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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