FKIE_CVE-2026-80994
Vulnerability from fkie_nvd - Published: 2026-09-11 20:19 - Updated: 2026-09-14 13:18
Severity
Summary
In the Linux kernel, the following vulnerability has been resolved:
net: openvswitch: fix flow mask use-after-free on flow deletion
The commit in the Fixes tag below made so flow->mask free is scheduled
via RCU right after it is removed from the flow table. The pointer
stays in the flow structure and it can be accessible while in the same
RCU critical section. This is done to avoid requiring ovs_mutex for
the ovs_flow_free().
However, while removing the flow during processing of CMD_DEL, we do
not take RCU read lock before the removal, and ovs_flow_cmd_fill_info()
uses the flow->mask pointer afterwards. The RCU read lock is taken,
but it's already late at that point. The comment on that line
acknowledges that the lock is cosmetic and doesn't serve a real purpose.
This leads to use-after-free if the RCU grace period passes between
removal and the filling. It is a short race window, but it is there
and can lead to a real crash in case memory allocation for the info
takes a bit longer:
BUG: KASAN: slab-use-after-free in __ovs_nla_put_key
net/openvswitch/flow_netlink.c:1996
BUG: KASAN: slab-use-after-free in ovs_nla_put_key+0x2463/0x2e30
net/openvswitch/flow_netlink.c:2250
Read of size 4 at addr ffff88801ee89970 by task ovs_flow_del_ec/9487
Call Trace:
<TASK>
__ovs_nla_put_key net/openvswitch/flow_netlink.c:1996
ovs_nla_put_key+0x2463/0x2e30 net/openvswitch/flow_netlink.c:2250
ovs_flow_cmd_fill_info+0x420/0x9c0 net/openvswitch/datapath.c:930
ovs_flow_cmd_del+0x53a/0x970 net/openvswitch/datapath.c:1467
...
netlink_rcv_skb+0x156/0x420 net/netlink/af_netlink.c:2556
</TASK>
Allocated by task 9487:
mask_alloc net/openvswitch/flow_table.c:967
flow_mask_insert net/openvswitch/flow_table.c:1012
ovs_flow_tbl_insert+0xea2/0x1a90 net/openvswitch/flow_table.c:1084
ovs_flow_cmd_new+0x7e3/0xd90 net/openvswitch/datapath.c:1086
...
netlink_rcv_skb+0x156/0x420 net/netlink/af_netlink.c:2556
Freed by task 9485:
rcu_free_sheaf+0x1e/0x100 mm/slub.c:5978
rcu_do_batch kernel/rcu/tree.c:2645
rcu_core+0x59c/0x10c0 kernel/rcu/tree.c:2897
handle_softirqs+0x1e4/0x9a0 kernel/softirq.c:622
...
instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062
ovs_flow_tbl_remove() must be called after the ovs_flow_cmd_fill_info()
to avoid this race. This also helps with cleaning up the forced cast
and the cosmetic RCU read lock. Before the commit in the Fixes tag the
order did not matter as long as the flow object itself was not freed.
A wider RCU critical section could be another option, but we have a
GFP_KERNEL allocation in the way.
Reported by Trend Micro's Zero Day Initiative as ZDI-CAN-32042.
References
Impacted products
| Vendor | Product | Version |
|---|
{
"affected": [
{
"affectedData": [
{
"defaultStatus": "unaffected",
"product": "Linux",
"programFiles": [
"net/openvswitch/datapath.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"lessThan": "ea5f7b45b582665541ddfb77dce98611354af4ab",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
},
{
"lessThan": "18ce1a8b7499c016d4a893d9b1db80608f73745d",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
},
{
"lessThan": "c15ef9a5bf594f93a31de2ec2ec394e2a903519a",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
},
{
"lessThan": "64051fe200c7c759af71634bd2123552eaabb69a",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
},
{
"lessThan": "0ba5cbc2f049af94ec94ff6f64958545efc5eaa2",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
},
{
"lessThan": "ac73e3af571da06c1d1cfe3f0f00dc978b851700",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
},
{
"lessThan": "7f072b84afd05a77963eb1872f7174e280661dce",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
},
{
"lessThan": "4e30317ff67a2eb12b4d890d39f72fd7e7117d48",
"status": "affected",
"version": "56c19868e115fcf8d62d843e1b9616bb9837d0db",
"versionType": "git"
}
]
},
{
"defaultStatus": "affected",
"product": "Linux",
"programFiles": [
"net/openvswitch/datapath.c"
],
"repo": "https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git",
"vendor": "Linux",
"versions": [
{
"status": "affected",
"version": "3.16"
},
{
"lessThan": "3.16",
"status": "unaffected",
"version": "0",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.10.*",
"status": "unaffected",
"version": "5.10.270",
"versionType": "semver"
},
{
"lessThanOrEqual": "5.15.*",
"status": "unaffected",
"version": "5.15.221",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.1.*",
"status": "unaffected",
"version": "6.1.188",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.6.*",
"status": "unaffected",
"version": "6.6.157",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.12.*",
"status": "unaffected",
"version": "6.12.109",
"versionType": "semver"
},
{
"lessThanOrEqual": "6.18.*",
"status": "unaffected",
"version": "6.18.50",
"versionType": "semver"
},
{
"lessThanOrEqual": "7.2.*",
"status": "unaffected",
"version": "7.2.4",
"versionType": "semver"
},
{
"lessThanOrEqual": "*",
"status": "unaffected",
"version": "7.3-rc1",
"versionType": "original_commit_for_fix"
}
]
}
],
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67"
}
],
"cveTags": [],
"descriptions": [
{
"lang": "en",
"value": "In the Linux kernel, the following vulnerability has been resolved:\n\nnet: openvswitch: fix flow mask use-after-free on flow deletion\n\nThe commit in the Fixes tag below made so flow-\u003emask free is scheduled\nvia RCU right after it is removed from the flow table. The pointer\nstays in the flow structure and it can be accessible while in the same\nRCU critical section. This is done to avoid requiring ovs_mutex for\nthe ovs_flow_free().\n\nHowever, while removing the flow during processing of CMD_DEL, we do\nnot take RCU read lock before the removal, and ovs_flow_cmd_fill_info()\nuses the flow-\u003emask pointer afterwards. The RCU read lock is taken,\nbut it\u0027s already late at that point. The comment on that line\nacknowledges that the lock is cosmetic and doesn\u0027t serve a real purpose.\n\nThis leads to use-after-free if the RCU grace period passes between\nremoval and the filling. It is a short race window, but it is there\nand can lead to a real crash in case memory allocation for the info\ntakes a bit longer:\n\n BUG: KASAN: slab-use-after-free in __ovs_nla_put_key\n net/openvswitch/flow_netlink.c:1996\n BUG: KASAN: slab-use-after-free in ovs_nla_put_key+0x2463/0x2e30\n net/openvswitch/flow_netlink.c:2250\n Read of size 4 at addr ffff88801ee89970 by task ovs_flow_del_ec/9487\n\n Call Trace:\n \u003cTASK\u003e\n __ovs_nla_put_key net/openvswitch/flow_netlink.c:1996\n ovs_nla_put_key+0x2463/0x2e30 net/openvswitch/flow_netlink.c:2250\n ovs_flow_cmd_fill_info+0x420/0x9c0 net/openvswitch/datapath.c:930\n ovs_flow_cmd_del+0x53a/0x970 net/openvswitch/datapath.c:1467\n ...\n netlink_rcv_skb+0x156/0x420 net/netlink/af_netlink.c:2556\n \u003c/TASK\u003e\n\n Allocated by task 9487:\n mask_alloc net/openvswitch/flow_table.c:967\n flow_mask_insert net/openvswitch/flow_table.c:1012\n ovs_flow_tbl_insert+0xea2/0x1a90 net/openvswitch/flow_table.c:1084\n ovs_flow_cmd_new+0x7e3/0xd90 net/openvswitch/datapath.c:1086\n ...\n netlink_rcv_skb+0x156/0x420 net/netlink/af_netlink.c:2556\n\n Freed by task 9485:\n rcu_free_sheaf+0x1e/0x100 mm/slub.c:5978\n rcu_do_batch kernel/rcu/tree.c:2645\n rcu_core+0x59c/0x10c0 kernel/rcu/tree.c:2897\n handle_softirqs+0x1e4/0x9a0 kernel/softirq.c:622\n ...\n instr_sysvec_apic_timer_interrupt arch/x86/kernel/apic/apic.c:1062\n\novs_flow_tbl_remove() must be called after the ovs_flow_cmd_fill_info()\nto avoid this race. This also helps with cleaning up the forced cast\nand the cosmetic RCU read lock. Before the commit in the Fixes tag the\norder did not matter as long as the flow object itself was not freed.\n\nA wider RCU critical section could be another option, but we have a\nGFP_KERNEL allocation in the way.\n\nReported by Trend Micro\u0027s Zero Day Initiative as ZDI-CAN-32042."
}
],
"id": "CVE-2026-80994",
"lastModified": "2026-09-14T13:18:54.043",
"metrics": {
"cvssMetricV31": [
{
"cvssData": {
"attackComplexity": "LOW",
"attackVector": "LOCAL",
"availabilityImpact": "HIGH",
"baseScore": 7.8,
"baseSeverity": "HIGH",
"confidentialityImpact": "HIGH",
"integrityImpact": "HIGH",
"privilegesRequired": "LOW",
"scope": "UNCHANGED",
"userInteraction": "NONE",
"vectorString": "CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H",
"version": "3.1"
},
"exploitabilityScore": 1.8,
"impactScore": 5.9,
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"type": "Secondary"
}
]
},
"published": "2026-09-11T20:19:06.357",
"references": [
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/0ba5cbc2f049af94ec94ff6f64958545efc5eaa2"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/18ce1a8b7499c016d4a893d9b1db80608f73745d"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/4e30317ff67a2eb12b4d890d39f72fd7e7117d48"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/64051fe200c7c759af71634bd2123552eaabb69a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/7f072b84afd05a77963eb1872f7174e280661dce"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ac73e3af571da06c1d1cfe3f0f00dc978b851700"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/c15ef9a5bf594f93a31de2ec2ec394e2a903519a"
},
{
"source": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"url": "https://git.kernel.org/stable/c/ea5f7b45b582665541ddfb77dce98611354af4ab"
}
],
"sourceIdentifier": "416baaa9-dc9f-4396-8d5f-8c081fb06d67",
"vulnStatus": "Received"
}
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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.
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- 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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The MITRE ATT&CK techniques below are AI-generated suggestions, inferred from the description of the
vulnerability by the CIRCL/vulnerability-attack-technique-classification-roberta-base
model, served locally by ML-Gateway.
They have not been verified by an analyst and are provided for guidance only.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
The approach is described in our paper Mapping CVEs to MITRE ATT&CK Techniques: A Curated Gold-Set Classifier and the Limits of LLM-Assisted Label Expansion.
Browse all ATT&CK techniques and the vulnerabilities related to each.
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Related by attack behaviour
Vulnerabilities whose description is nearest to this one in the vector space of the CIRCL/vulnerability-attack-technique-biencoder model. This is a similarity search over the bi-encoder space (plain cosine), not a classification, and it has no measured accuracy.
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