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CVE-2026-74484— binfmt_misc: don't let an 'F' entry pin its own instance

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 4.8版本存在安全漏洞，该漏洞源于binfmt_misc的“F”条目固定自身实例，导致文件无法关闭，可能造成拒绝服务和用户命名空间资源泄漏。

AI Predicted 7.8 Difficulty: Moderate EPSS 0.17% · P6

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 21ca59b365c091d583f36ac753eaa8baf947be6f< 1cc2decee06acc939337304e9b3f737fd5d8c4bd affected
21ca59b365c091d583f36ac753eaa8baf947be6f< 4dad8ca637d44d5a6d5c23fa80c9e2e455198c2b affected
21ca59b365c091d583f36ac753eaa8baf947be6f< 098e92fe0f1bde5af99c8cf504f13f01ef139f85 affected
21ca59b365c091d583f36ac753eaa8baf947be6f< 79055d82772b9584f259b747fe40ff56a076678d affected
6.7 affected
< 6.7 unaffected
6.12.103≤ 6.12.* unaffected
6.18.44≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-74484

Vulnerability Information
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Vulnerability Title
binfmt_misc: don't let an 'F' entry pin its own instance
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: binfmt_misc: don't let an 'F' entry pin its own instance An entry registered with 'F' opens its interpreter at registration time and holds that file until the entry is freed. Any entry nobody removes by hand only gets closed once the binfmt_misc superblock is shut down. If the interpreter lives on a mount that keeps that superblock alive the two pin each other: binfmt_misc sb -> inode -> entry -> interp_file -> vfsmount -> binfmt_misc sb TL;DR the file is never closed. Once the mount namespace is gone there is nothing left to unregister through either. There are two ways to trigger this bug: - Point the interpreter at the instance itself. Its files are regular files owned by the mounter and both bm_get_inode() and simple_fill_super() leave i_op at empty_iops. So notify_change() falls back to simple_setattr() and chmod +x works. We never set SB_I_NOEXEC and so open_exec() accepts it. - Use the instance as an overlayfs lower layer. The overlay superblock holds a clone_private_mount() of every layer until it is destroyed and that clone is in no namespace. So umount_tree() never reaches it. That's a DoS. And it isn't only the superblock that leaks. It pins the user namespace it was mounted in, so every iteration permanently eats one of the caller's user namespace charges. So let's just do the sane thing. SB_I_NOEXEC makes open_exec() fail on the instance's own files and s_stack_depth makes overlayfs reject the layer before it ever takes a clone. That also covers the ecryptfs and fuse passthrough variants. What 'F' promises is unchanged. The stable tag is narrower than the Fixes tags on purpose. Before sandboxed mounts this needed global root against the single instance everyone shares, and the change doesn't apply to those trees anyway. Note that SB_I_NODEV is implicitly raised for userns mounts but raise it explicitly here as well.
Source: CVE Program / CVE List V5
CVSS Information
N/A
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 4.8版本存在安全漏洞，该漏洞源于binfmt_misc的“F”条目固定自身实例，导致文件无法关闭，可能造成拒绝服务和用户命名空间资源泄漏。
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 21ca59b365c091d583f36ac753eaa8baf947be6f ~ 1cc2decee06acc939337304e9b3f737fd5d8c4bd -
Linux Linux 6.7 -

II. Public POCs for CVE-2026-74484

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III. Intelligence Information for CVE-2026-74484

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Patches & Fixes for CVE-2026-74484 (4)

Same Patch Batch · Linux · 2026-08-15 · 845 CVEs total

CVE-2026-74280 10.0 CRITICAL crypto: marvell/octeontx - fix DMA cleanup using wrong loop index
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72221 9.8 CRITICAL sunrpc: wait for in-flight TLS handshake callback when cancel loses race
CVE-2026-72466 9.8 CRITICAL xprtrdma: Fix bcall rep leak and unbounded peek
CVE-2026-72323 9.8 CRITICAL ipv4: igmp: Fix potential UAF in igmp_gq_start_timer()
CVE-2026-72463 9.8 CRITICAL xfrm: Fix dev use-after-free in xfrm async resumption
CVE-2026-72069 9.8 CRITICAL locking/rt: Fix the incorrect RCU protection in rt_spin_unlock()
CVE-2026-72339 9.8 CRITICAL qede: fix off-by-one in BD ring consumption on build_skb failure
CVE-2026-72065 9.8 CRITICAL net: mana: Validate the packet length reported by the NIC
CVE-2026-72064 9.8 CRITICAL net: mana: Sync page pool RX frags for CPU
CVE-2026-74255 9.8 CRITICAL tipc: fix UAF in tipc_l2_send_msg()
CVE-2026-74376 9.8 CRITICAL md/raid10: reset read_slot when reusing r10bio for discard
CVE-2026-72234 9.8 CRITICAL batman-adv: access unicast_ttvn skb->data only after skb realloc
CVE-2026-72041 9.8 CRITICAL espintcp: use sk_msg_free_partial to fix partial send

Showing top 20 of 845 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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