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CVE-2026-63929— iio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()

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基金会开源的一款操作系统内核。 Linux kernel 6.11版本存在安全漏洞，该漏洞源于iio_buffer_enqueue_dmabuf()函数中的DMA fencing释放问题，导致每个缓冲区入队时永久泄漏一个kmalloc-128分配。

AI Predicted 5.5 Difficulty: Easy EPSS 0.21% · P11

Possible ATT&CK Techniques 1 AI

T1499 · Endpoint Denial of Service

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f< 9678aeed8b77d495a417dd057d479f3733094019 affected
3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f< 3412a95afaa5d3262008dfc34f3c7be33d8151dc affected
3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f< 96cdeaba6a008503455b78a9641c05c2a886a7ec affected
3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f< a093999355084bdbfe6e97f1dd232e58a1525f0b affected
6.11 affected
< 6.11 unaffected
6.12.93≤ 6.12.* unaffected
6.18.35≤ 6.18.* unaffected
… +2 more rows
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I. Basic Information for CVE-2026-63929

Vulnerability Information
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Vulnerability Title
iio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf()
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: iio: buffer: Fix DMA fence leak in iio_buffer_enqueue_dmabuf() iio_buffer_enqueue_dmabuf() allocates a struct iio_dma_fence (104 bytes, kmalloc-128) via kmalloc_obj()+dma_fence_init(), which sets the initial kref to 1. It then calls dma_resv_add_fence() which takes a second reference (kref=2), and stores a raw pointer in block->fence. On the success path the function returns without calling dma_fence_put() to release the initial reference, so every buffer enqueue permanently leaks one kmalloc-128 allocation. The iio_buffer_cleanup() work item only releases the temporary reference taken during completion signalling by iio_buffer_signal_dmabuf_done(); the initial reference from dma_fence_init() is never released. With four iio_rwdev instances at 240kHz and 512 samples per buffer, this produces ~1875 kmalloc-128 allocations per second matching the observed slab growth exactly. A test with ftrace confirmed that the dma_fence_destroy event was never triggered. Fix by calling dma_fence_put() after dma_resv_add_fence(), transferring ownership of the fence to the DMA reservation object. The DMA fence then gets properly discarded after being signalled.
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基金会开源的一款操作系统内核。 Linux kernel 6.11版本存在安全漏洞，该漏洞源于iio_buffer_enqueue_dmabuf()函数中的DMA fencing释放问题，导致每个缓冲区入队时永久泄漏一个kmalloc-128分配。
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 3e26d9f08fbe0b73e951a5e810fdb7a332b7e37f ~ 9678aeed8b77d495a417dd057d479f3733094019 -
Linux Linux 6.11 -

II. Public POCs for CVE-2026-63929

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III. Intelligence Information for CVE-2026-63929

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Patches & Fixes for CVE-2026-63929 (4)

Same Patch Batch · Linux · 2026-07-19 · 429 CVEs total

CVE-2026-63795 10.0 CRITICAL 9p: avoid putting oldfid in p9_client_walk() error path
CVE-2026-64037 9.8 CRITICAL wifi: iwlwifi: mld: fix TSO segmentation explosion when AMSDU is disabled
CVE-2026-63993 9.8 CRITICAL vxlan: do not reuse cached ip_hdr() value after skb_tunnel_check_pmtu()
CVE-2026-63994 9.8 CRITICAL tunnels: load network headers after skb_cow() in iptunnel_pmtud_build_icmp[v6]()
CVE-2026-64142 9.8 CRITICAL ksmbd: close durable scavenger races against m_fp_list lookups
CVE-2026-64000 9.8 CRITICAL net: hsr: fix potential OOB access in supervision frame handling
CVE-2026-64046 9.8 CRITICAL net: tls: prevent chain-after-chain in plain text SG
CVE-2026-64162 9.8 CRITICAL idpf: fix read_dev_clk_lock spinlock init in idpf_ptp_init()
CVE-2026-53399 9.8 CRITICAL nfsd: release layout stid on setlease failure
CVE-2026-53398 9.8 CRITICAL NFSD: Fix SECINFO_NO_NAME decode error cleanup
CVE-2026-64007 9.8 CRITICAL netfilter: synproxy: refresh tcphdr after skb_ensure_writable
CVE-2026-63825 9.8 CRITICAL gcov: use atomic counter updates to fix concurrent access crashes
CVE-2026-64016 9.8 CRITICAL ksmbd: fix durable reconnect error path file lifetime
CVE-2026-63800 9.8 CRITICAL pNFS: Fix use-after-free in pnfs_update_layout()
CVE-2026-63808 9.8 CRITICAL exfat: fix potential use-after-free in exfat_find_dir_entry()
CVE-2026-64025 9.8 CRITICAL bpf, skmsg: fix verdict sk_data_ready racing with ktls rx
CVE-2026-64125 9.8 CRITICAL net: bcmgenet: keep RBUF EEE/PM disabled
CVE-2026-64033 9.8 CRITICAL RDMA/rtrs: Fix use-after-free in path file creation cleanup
CVE-2026-64089 9.8 CRITICAL batman-adv: tt: fix negative last_changeset_len
CVE-2026-64035 9.8 CRITICAL igc: set tx buffer type for SMD frames

Showing top 20 of 429 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

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