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CVE-2026-74506— afs: Fix UAF when sending a message

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 5.8版本存在安全漏洞,该漏洞源于afs_make_call()函数在发送异步消息时存在竞态条件,可能导致释放后重用。

CVSS 7.8 · High EPSS 0.12% · P3

Affected Version Matrix 8

VendorProduct Version RangeStatus
Linux Linux e49c7b2f6de7ff81ca34c56e4eeb4fa740c099f2< c0d3b81f703b2a9e37fe1347610a50cdf0078c27 affected
e49c7b2f6de7ff81ca34c56e4eeb4fa740c099f2< daaa726b14fc3026a6b328614d312b698f62f391 affected
e49c7b2f6de7ff81ca34c56e4eeb4fa740c099f2< 4af1ec68d54b3871155914d584fb10669c41a861 affected
5.8 affected
< 5.8 unaffected
6.18.44≤ 6.18.* unaffected
7.1.8≤ 7.1.* unaffected
7.2≤ * unaffected
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I. Basic Information for CVE-2026-74506

Vulnerability Information

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Vulnerability Title
afs: Fix UAF when sending a message
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: afs: Fix UAF when sending a message In afs_make_call(), there's a race with async call reception and destruction. If a call is dispatched that doesn't have call->write_iter set (used to specify the data content for FS.StoreData), then the first rxrpc_kernel_send_data() will not set MSG_MORE in the msghdr. Once rxrpc_send_data() queues the last request packet, the response could come in at any time and cause the call to be completed and put. However, afs_make_call() will look at the call again to see it ->write_iter should be handled - something it's only allowed to do if it has its own ref on the call. Whilst this is the case for synchronous calls, it isn't true for async calls such as FS.FetchData. There's also a potential UAF in afs_make_call() in the event that an asynchronous call is being sent, but the call fails in some way (e.g. it gets aborted from the server). The problem there is that afs_make_call() tries to abort a call if the rxrpc send fails, but the asynchronous notification from rxrpc may have caused the afs_call to be torn down. generic/650 plays games with randomly taking CPUs offline, and can interject a significant delay such that the call is deallocated before afs_make_call() gets to check call->write_iter - and a UAF ensues (caught by KASAN). BUG: KASAN: slab-use-after-free in afs_make_call+0x1c90/0x2210 [kafs] Read of size 8 at addr ffff888035e050e8 by task fsstress/1409 Fix this by making afs_make_op_call() give the op->call its own ref rather than transferring the caller's ref to it and then dropping the ref when afs_make_call() returns. This also means that the afs_make_call() func never loses its ref on the call now.
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 5.8版本存在安全漏洞,该漏洞源于afs_make_call()函数在发送异步消息时存在竞态条件,可能导致释放后重用。
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 e49c7b2f6de7ff81ca34c56e4eeb4fa740c099f2 ~ c0d3b81f703b2a9e37fe1347610a50cdf0078c27 -
Linux Linux 5.8 -

II. Public POCs for CVE-2026-74506

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III. Intelligence Information for CVE-2026-74506

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Patches & Fixes for CVE-2026-74506 (2)

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-2026-74475 10.0 CRITICAL vxlan: use neigh_ha_snapshot() in route_shortcircuit()
CVE-2026-72407 10.0 CRITICAL geneve: validate inner network offset in geneve_gro_complete()
CVE-2026-74309 10.0 CRITICAL vdpa/octeon_ep: fix IRQ-to-ring mapping in interrupt handler
CVE-2026-72408 10.0 CRITICAL geneve: gate GRO hint in geneve_gro_complete() on gs->gro_hint
CVE-2026-72421 10.0 CRITICAL ipv4: fib: Don't ignore error route in local/main tables.
CVE-2026-74279 10.0 CRITICAL crypto: cavium/cpt - fix DMA cleanup using wrong loop index
CVE-2026-72493 9.9 CRITICAL net: serialize netif_running() check in enqueue_to_backlog()
CVE-2026-72084 9.8 CRITICAL scsi: target: Bound PR-OUT TransportID parsing to the received buffer
CVE-2026-72249 9.8 CRITICAL netfilter: flowtable: use dst in this direction when pushing IPIP header
CVE-2026-72248 9.8 CRITICAL netfilter: flowtable: support IPIP tunnel with direct xmit
CVE-2026-72494 9.8 CRITICAL RDMA/irdma: Replace waitqueue and flag with completion
CVE-2026-72220 9.8 CRITICAL sunrpc: harden rq_procinfo lifecycle to prevent double-free
CVE-2026-74345 9.8 CRITICAL RDMA/siw: Fix endpoint/socket association handling
CVE-2026-74255 9.8 CRITICAL tipc: fix UAF in tipc_l2_send_msg()
CVE-2026-72221 9.8 CRITICAL sunrpc: wait for in-flight TLS handshake callback when cancel loses race
CVE-2026-72226 9.8 CRITICAL batman-adv: tt: prevent TVLV OOB check overflow
CVE-2026-74428 9.8 CRITICAL rxrpc: Fix double unlock in rxrpc_recvmsg()
CVE-2026-72083 9.8 CRITICAL scsi: target: core: Fix iSCSI ISID use-after-free in REGISTER AND MOVE
CVE-2026-72234 9.8 CRITICAL batman-adv: access unicast_ttvn skb->data only after skb realloc

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

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