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CVE-2026-80994— net: openvswitch: fix flow mask use-after-free on flow deletion

Quick assessment

Affected
Linux Linux
Exploitation
No confirmed in-the-wild exploitation; assess based on exposure
Recommended action
Check the vendor advisory and references for a fixed version. If immediate upgrade is impossible, restrict exposure and increase monitoring.

Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于处理CMD_DEL删除流时未先获取RCU读锁，导致ovs_flow_cmd_fill_info()在流被释放后使用flow->mask指针，可能造成释放后重用并导致崩溃。

CVSS 7.8 · High EPSS 0.17% · P6

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 56c19868e115fcf8d62d843e1b9616bb9837d0db< ea5f7b45b582665541ddfb77dce98611354af4ab affected
56c19868e115fcf8d62d843e1b9616bb9837d0db< 18ce1a8b7499c016d4a893d9b1db80608f73745d affected
56c19868e115fcf8d62d843e1b9616bb9837d0db< c15ef9a5bf594f93a31de2ec2ec394e2a903519a affected
56c19868e115fcf8d62d843e1b9616bb9837d0db< 64051fe200c7c759af71634bd2123552eaabb69a affected
56c19868e115fcf8d62d843e1b9616bb9837d0db< 0ba5cbc2f049af94ec94ff6f64958545efc5eaa2 affected
56c19868e115fcf8d62d843e1b9616bb9837d0db< ac73e3af571da06c1d1cfe3f0f00dc978b851700 affected
56c19868e115fcf8d62d843e1b9616bb9837d0db< 7f072b84afd05a77963eb1872f7174e280661dce affected
56c19868e115fcf8d62d843e1b9616bb9837d0db< 4e30317ff67a2eb12b4d890d39f72fd7e7117d48 affected
… +10 more rows
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I. Basic Information for CVE-2026-80994

Vulnerability Information
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Vulnerability Title
net: openvswitch: fix flow mask use-after-free on flow deletion
Source: CVE Program / CVE List V5
Vulnerability Description
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.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会开源的一个操作系统内核。 Linux kernel存在安全漏洞，该漏洞源于处理CMD_DEL删除流时未先获取RCU读锁，导致ovs_flow_cmd_fill_info()在流被释放后使用flow->mask指针，可能造成释放后重用并导致崩溃。
Source: CNNVD (China National Vulnerability Database)
CVSS Information
N/A
Source: CNNVD (China National Vulnerability Database)
Vulnerability Type
N/A
Source: CNNVD (China National Vulnerability Database)

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 56c19868e115fcf8d62d843e1b9616bb9837d0db ~ ea5f7b45b582665541ddfb77dce98611354af4ab -
Linux Linux 3.16 -

II. Public POCs for CVE-2026-80994

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III. Intelligence Information for CVE-2026-80994

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Patches & Fixes for CVE-2026-80994 (8)

Same Patch Batch · Linux · 2026-09-11 · 430 CVEs total

CVE-2026-89703 9.8 CRITICAL nfsd: set SC_STATUS_FREED in nfsd4_drop_revoked_stid for delegations
CVE-2026-89689 9.8 CRITICAL nfsd: don't free session slots that are still in use
CVE-2026-89558 9.8 CRITICAL md/raid10: fix still_degraded being inverted in raid10_sync_request()
CVE-2026-89555 9.8 CRITICAL mpls: reload header after pskb_may_pull()
CVE-2026-89550 9.8 CRITICAL SUNRPC: svcauth_gss: enforce krb5 token minimum length
CVE-2026-89551 9.8 CRITICAL SUNRPC: xdr_buf_trim: clamp buf->len to avoid underflow
CVE-2026-89546 9.8 CRITICAL SUNRPC: close backchannel before destroying callback service
CVE-2026-89542 9.8 CRITICAL SUNRPC: harden gss_krb5_unwrap_v2 against short tokens
CVE-2026-89541 9.8 CRITICAL SUNRPC: harden gss_unwrap_resp_priv length checks
CVE-2026-89538 9.8 CRITICAL SUNRPC: Reject krb5 v2 wrap tokens with oversized ec field
CVE-2026-89536 9.8 CRITICAL SUNRPC: wait for in-flight client TLS handshake callback
CVE-2026-89533 9.8 CRITICAL svcrdma: Fix offset arithmetic in read_chunk_range
CVE-2026-89530 9.8 CRITICAL svcrdma: Reject inline replies that overflow the pull-up buffer
CVE-2026-89526 9.8 CRITICAL svcrdma: Validate Read chunk positions before reconstruction
CVE-2026-81002 9.8 CRITICAL xdp: fix zero-copy frame layout
CVE-2026-89482 9.8 CRITICAL nvme-tcp: do not accept C2HData based on blk_rq_payload_bytes() alone
CVE-2026-89478 9.8 CRITICAL sctp: drop a chunk if its transport was removed
CVE-2026-89479 9.8 CRITICAL sctp: stop processing a packet once its association is deleted
CVE-2026-89485 9.8 CRITICAL lockd: pin next file across nlm_inspect_file lock-drop
CVE-2026-80986 9.8 CRITICAL net/smc: bound the peer rkey counts in SMC-Rv2 LLC messages

Showing top 20 of 430 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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