fkie_cve-2025-68245
Vulnerability from fkie_nvd
Published
2025-12-16 15:15
Modified
2025-12-18 15:08
Severity ?
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: netpoll: fix incorrect refcount handling causing incorrect cleanup
commit efa95b01da18 ("netpoll: fix use after free") incorrectly
ignored the refcount and prematurely set dev->npinfo to NULL during
netpoll cleanup, leading to improper behavior and memory leaks.
Scenario causing lack of proper cleanup:
1) A netpoll is associated with a NIC (e.g., eth0) and netdev->npinfo is
allocated, and refcnt = 1
- Keep in mind that npinfo is shared among all netpoll instances. In
this case, there is just one.
2) Another netpoll is also associated with the same NIC and
npinfo->refcnt += 1.
- Now dev->npinfo->refcnt = 2;
- There is just one npinfo associated to the netdev.
3) When the first netpolls goes to clean up:
- The first cleanup succeeds and clears np->dev->npinfo, ignoring
refcnt.
- It basically calls `RCU_INIT_POINTER(np->dev->npinfo, NULL);`
- Set dev->npinfo = NULL, without proper cleanup
- No ->ndo_netpoll_cleanup() is either called
4) Now the second target tries to clean up
- The second cleanup fails because np->dev->npinfo is already NULL.
* In this case, ops->ndo_netpoll_cleanup() was never called, and
the skb pool is not cleaned as well (for the second netpoll
instance)
- This leaks npinfo and skbpool skbs, which is clearly reported by
kmemleak.
Revert commit efa95b01da18 ("netpoll: fix use after free") and adds
clarifying comments emphasizing that npinfo cleanup should only happen
once the refcount reaches zero, ensuring stable and correct netpoll
behavior.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: netpoll: fix incorrect refcount handling causing incorrect cleanup\n\ncommit efa95b01da18 (\"netpoll: fix use after free\") incorrectly\nignored the refcount and prematurely set dev-\u003enpinfo to NULL during\nnetpoll cleanup, leading to improper behavior and memory leaks.\n\nScenario causing lack of proper cleanup:\n\n1) A netpoll is associated with a NIC (e.g., eth0) and netdev-\u003enpinfo is\n allocated, and refcnt = 1\n - Keep in mind that npinfo is shared among all netpoll instances. In\n this case, there is just one.\n\n2) Another netpoll is also associated with the same NIC and\n npinfo-\u003erefcnt += 1.\n - Now dev-\u003enpinfo-\u003erefcnt = 2;\n - There is just one npinfo associated to the netdev.\n\n3) When the first netpolls goes to clean up:\n - The first cleanup succeeds and clears np-\u003edev-\u003enpinfo, ignoring\n refcnt.\n - It basically calls `RCU_INIT_POINTER(np-\u003edev-\u003enpinfo, NULL);`\n - Set dev-\u003enpinfo = NULL, without proper cleanup\n - No -\u003endo_netpoll_cleanup() is either called\n\n4) Now the second target tries to clean up\n - The second cleanup fails because np-\u003edev-\u003enpinfo is already NULL.\n * In this case, ops-\u003endo_netpoll_cleanup() was never called, and\n the skb pool is not cleaned as well (for the second netpoll\n instance)\n - This leaks npinfo and skbpool skbs, which is clearly reported by\n kmemleak.\n\nRevert commit efa95b01da18 (\"netpoll: fix use after free\") and adds\nclarifying comments emphasizing that npinfo cleanup should only happen\nonce the refcount reaches zero, ensuring stable and correct netpoll\nbehavior."
}
],
"id": "CVE-2025-68245",
"lastModified": "2025-12-18T15:08:06.237",
"metrics": {},
"published": "2025-12-16T15:15:53.767",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/49c8d2c1f94cc2f4d1a108530d7ba52614b874c2"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4afd4ebbad52aa146838ec23082ba393e426a2bb"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/890472d6fbf062e6de7fdd56642cb305ab79d669"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/8e6a50edad11e3e1426e4c29e7aa6201f3468ac2"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9a51b5ccd1c79afec1c03a4e1e6688da52597556"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/9b0bb18b4b9dc017c1825a2c5e763615e34a1593"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c645693180a98606c430825223d2029315d85e9d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c79a6d9da29219616b118a3adce9a14cd30f9bd0"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Awaiting Analysis"
}
Loading…
Loading…
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.
Loading…
Loading…