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CVE-2026-80633— iommufd: Take dma_resv lock before dma_buf_unpin() in release path

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.

在 Linux 内核中，以下漏洞已得到修复： iommufd：在 release 路径中，在调用 dma_buf_unpin() 之前获取 dma_resv 锁 要求调用者必须持有导出者的 锁： 在调用 时未获取该锁，导致每次通过 或 释放基于 DMABUF 的 的最后一个引用时，都会触发一个 。此问题在运行 时被发现： 修复方法是在 中，在调用 时获取 锁，以符合 的约定。由于 会在内部获取预留锁（reservation lock），因此它必须保持在加锁区域之外。

CVSS 8.8 · High EPSS 0.15% · P5

Affected Version Matrix 6

VendorProduct Version RangeStatus
Linux Linux 8c5f9645c3893f0db679d9affe4fe4e665b990dd< cc69d0332421fd2943b66dbe5e597bf4fd5af126 affected
8c5f9645c3893f0db679d9affe4fe4e665b990dd< e745cd2c749e557c14a15ac931761c3f58c24489 affected
7.1 affected
< 7.1 unaffected
7.1.5≤ 7.1.* unaffected
7.2≤ * unaffected
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I. Basic Information for CVE-2026-80633

Vulnerability Information
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Vulnerability Title
iommufd: Take dma_resv lock before dma_buf_unpin() in release path
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: iommufd: Take dma_resv lock before dma_buf_unpin() in release path dma_buf_unpin() requires the caller to hold the exporter's dma_resv lock: void dma_buf_unpin(struct dma_buf_attachment *attach) { ... dma_resv_assert_held(dmabuf->resv); ... } iopt_release_pages() calls dma_buf_unpin() without taking that lock, so every iommufd_ioas_destroy()/iommufd_ioas_unmap() that releases the last reference on a DMABUF-backed iopt_pages triggers a WARN. This was hit while running tools/testing/selftests/iommu/iommufd: WARNING: drivers/dma-buf/dma-buf.c:1137 at dma_buf_unpin+0x62/0x70 RIP: 0010:dma_buf_unpin+0x62/0x70 Call Trace: <TASK> dma_buf_unpin+0x62/0x70 iopt_release_pages+0xe4/0x190 iopt_unmap_iova_range+0x1c7/0x290 iopt_unmap_all+0x1a/0x30 iommufd_ioas_destroy+0x1d/0x50 iommufd_fops_release+0x93/0x150 __fput+0xfc/0x2c0 __x64_sys_close+0x3d/0x80 do_syscall_64+0x65/0x180 </TASK> Take the dma_resv lock around dma_buf_unpin() in iopt_release_pages(), matching the iopt_map_dmabuf() convention. dma_buf_detach() acquires the reservation lock internally, so it must remain outside the locked region.
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:C/C:H/I:H/A:H
Source: CVE Program / CVE List V5
Vulnerability Type
N/A
Source: CVE Program / CVE List V5

Affected Products

Vendor Product Affected Versions CPE Subscribe
Linux Linux 8c5f9645c3893f0db679d9affe4fe4e665b990dd ~ cc69d0332421fd2943b66dbe5e597bf4fd5af126 -
Linux Linux 7.1 -

II. Public POCs for CVE-2026-80633

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III. Intelligence Information for CVE-2026-80633

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Patches & Fixes for CVE-2026-80633 (2)

Same Patch Batch · Linux · 2026-08-28 · 135 CVEs total

CVE-2026-80634 9.8 CRITICAL netfilter: flowtable: avoid num_encaps underflow on bridge VLAN untag
CVE-2026-80694 9.8 CRITICAL net: ethernet: mtk_eth_soc: pass eth to mtk_handle_irq_rx in poll_controller
CVE-2026-80681 9.8 CRITICAL vxlan: re-fetch eth header after route_shortcircuit()
CVE-2026-80674 9.8 CRITICAL ntfs: validate resident attribute lists and harden the validator
CVE-2026-80673 9.8 CRITICAL ntfs: bound the look-ahead attribute-list entry in ntfs_external_attr_find()
CVE-2026-80668 9.8 CRITICAL netfilter: nf_conntrack_expect: use conntrack GC to reap expectations
CVE-2026-80630 9.8 CRITICAL net/sched: sch_fq_codel: Do not call qdisc_tree_reduce_backlog during peek before restorin
CVE-2026-80617 9.8 CRITICAL net: airoha: fix foe_check_time allocation size
CVE-2026-80612 9.8 CRITICAL net: lwtunnel: Drop skb metadata before LWT encapsulation
CVE-2026-80714 9.8 CRITICAL ipvs: do not propagate one-packet flag to synced conns
CVE-2026-80609 9.8 CRITICAL qede: fix out-of-bounds check for cqe->len_list[]
CVE-2026-80600 9.8 CRITICAL batman-adv: dat: acquire ARP hw source only after skb realloc
CVE-2026-80693 9.3 CRITICAL idpf: bound interrupt-vector register fill to the allocated array
CVE-2026-80684 9.3 CRITICAL KVM: s390: pci: Fix NULL dereference on AIBV allocation failure
CVE-2026-80671 9.3 CRITICAL perf sched: Fix register_pid() overflow, strcpy, and BUG_ON
CVE-2026-80603 9.1 CRITICAL netfilter: nf_conntrack_irc: fix parse_dcc() off-by-one OOB read
CVE-2026-80670 9.1 CRITICAL perf tools: Use perf_env__get_cpu_topology() in machine__resolve()
CVE-2026-80722 8.8 HIGH wifi: mac80211: validate individual TWT params before driver setup
CVE-2026-80724 8.8 HIGH ptp: vmclock: prevent read-only mappings from becoming writable
CVE-2026-80683 8.8 HIGH Bluetooth: SCO: give the socket its own sco_conn reference

Showing top 20 of 135 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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