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CVE-2026-74715— bpf: Fix netns reference imbalance in conntrack kfuncs

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 6.0版本存在安全漏洞，该漏洞源于BPF conntrack kfuncs中opts参数可指向共享map值，__bpf_nf_ct_lookup()和__bpf_nf_ct_alloc_entry()分别读取opts->netns_id导致网络命名空间引用不平衡，可能造成空指针解引用和内核崩溃。

CVSS 7.8 · High EPSS 0.17% · P6

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux aed8ee7feb44b6537af1e0b4f03365d42928be38< 4af94462c0ca2187a02a1a6641020ae888c74d5c affected
aed8ee7feb44b6537af1e0b4f03365d42928be38< e5e060eb63d10b41ab60fd955649479d99b38210 affected
aed8ee7feb44b6537af1e0b4f03365d42928be38< fdeba03fea78407a8c52faa99177c9f7f29f90eb affected
6.0 affected
< 6.0 unaffected
6.18.57≤ 6.18.* unaffected
7.1.9≤ 7.1.* unaffected
7.2≤ * unaffected
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I. Basic Information for CVE-2026-74715

Vulnerability Information
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Vulnerability Title
bpf: Fix netns reference imbalance in conntrack kfuncs
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix netns reference imbalance in conntrack kfuncs The opts argument of the BPF conntrack kfuncs can point to a shared map value. __bpf_nf_ct_lookup() and __bpf_nf_ct_alloc_entry() read opts->netns_id separately when acquiring and releasing the network namespace reference. The reference imbalance can occur as follows: CPU 0 CPU 1 read opts->netns_id (-1) skip get_net_ns_by_id() write opts->netns_id (id) read opts->netns_id (id) put_net(net) /* no matching get */ The reverse transition leaks the reference. Repeating the unmatched put can destroy a live namespace and crash later users. The kernel reported: Oops: general protection fault, probably for non-canonical address KASAN: null-ptr-deref in range [0x00000000000000e8-0x00000000000000ef] RIP: 0010:bpf_prog_test_run_xdp+0x52c/0x1700 Call Trace: __sys_bpf+0x1662/0x50c0 __x64_sys_bpf+0x73/0xb0 do_syscall_64+0xf9/0x540 entry_SYSCALL_64_after_hwframe+0x77/0x7f Kernel panic - not syncing: Fatal exception Snapshot every input field of opts with READ_ONCE() before validating or using it. The netns_id snapshot keeps the namespace get/put pair balanced, while the other snapshots keep the remaining options from changing partway through an invocation. The individual reads can still observe an inconsistent combination during a concurrent update, but each selected field value remains stable for that invocation.
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 6.0版本存在安全漏洞，该漏洞源于BPF conntrack kfuncs中opts参数可指向共享map值，__bpf_nf_ct_lookup()和__bpf_nf_ct_alloc_entry()分别读取opts->netns_id导致网络命名空间引用不平衡，可能造成空指针解引用和内核崩溃。
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 aed8ee7feb44b6537af1e0b4f03365d42928be38 ~ 4af94462c0ca2187a02a1a6641020ae888c74d5c -
Linux Linux 6.0 -

II. Public POCs for CVE-2026-74715

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III. Intelligence Information for CVE-2026-74715

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Patches & Fixes for CVE-2026-74715 (2)

Other References for CVE-2026-74715 (1)

Same Patch Batch · Linux · 2026-08-22 · 149 CVEs total

CVE-2026-74705 10.0 CRITICAL udp: fix potential use-after-free in tunnel segmentation
CVE-2026-74612 10.0 CRITICAL veth: fix skb length accounting after XDP frag adjustment
CVE-2026-74723 9.8 CRITICAL btrfs: lzo: reject inline extents without valid headers
CVE-2026-74669 9.8 CRITICAL ipvs: clear IPv4 options after rebasing tunnel ICMP errors
CVE-2026-74608 9.8 CRITICAL smb: client: Fix use-after-free in cifs_try_adding_channels()
CVE-2026-74688 9.8 CRITICAL sctp: clear control chunk transport if it is being removed
CVE-2026-74727 9.8 CRITICAL ovpn: skip rehash for peers already removed from by_id
CVE-2026-74628 9.8 CRITICAL net/x25: fix use-after-free of the socket by its timers
CVE-2026-74662 9.8 CRITICAL inet: frags: publish queues before arming timer
CVE-2026-74597 9.8 CRITICAL ip6_tunnel: clear skb2->cb[] in ip6ip6_err()
CVE-2026-74611 9.8 CRITICAL tls: rx: restore msg_iter before TLS 1.3 optimistic retry
CVE-2026-74616 9.8 CRITICAL xdp: reject clones that overrun skb_shared_info tailroom
CVE-2026-74586 9.8 CRITICAL sctp: clear new_transport when removing a peer
CVE-2026-74587 9.8 CRITICAL sctp: fix use-after-free of cached ASCONF chunk
CVE-2026-74588 9.8 CRITICAL sctp: keep chunk->transport in step with the list it is queued on
CVE-2026-74617 9.8 CRITICAL dibs: initialise dibs->lock in dibs_dev_alloc()
CVE-2026-74591 9.8 CRITICAL mm/filemap: __filemap_add_folio() restore index before retrying
CVE-2026-74730 9.8 CRITICAL NFS: Pin the 'struct nfs_server' during a FREE_STATEID call
CVE-2026-74712 9.3 CRITICAL vdpa/mlx5: Fix buffer length in create_direct_keys()
CVE-2026-74665 9.1 CRITICAL net: fix skb length accounting after generic XDP frag adjustment

Showing top 20 of 149 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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