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CVE-2026-31788— xen/privcmd: restrict usage in unprivileged domU

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基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于xen/privcmd驱动在非特权域中的使用限制不足，可能导致破坏安全启动功能。

CVSS 8.2 · High EPSS 0.20% · P10

Possible ATT&CK Techniques 1 AI

T1055 · Process Injection

Affected Version Matrix 18

VendorProduct Version RangeStatus
Linux Linux 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< 4eb245ff0d33b618e097a2c23de5df56d4ad6969 affected
1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< 3ee5b9e3de4b8bdd74183d83205481c91a9effc8 affected
1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< 87a803edb2ded911cb587c53bff179d2a2ed2a28 affected
1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< 1879319d790f7d57622cdc22807b60ea78b56b6d affected
1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< 78432d8f0372c71c518096395537fa12be7ff24e affected
1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< 389bae9a4409934e8b8d4dbdaaf02a3ae71cf8e4 affected
1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< cbede2e833da1893afbea9b3ff29b5dda23a4a91 affected
1c5de1939c204bde9cce87f4eb3d26e9f9eb732b< 453b8fb68f3641fea970db88b7d9a153ed2a37e8 affected
… +10 more rows
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I. Basic Information for CVE-2026-31788

Vulnerability Information
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Vulnerability Title
xen/privcmd: restrict usage in unprivileged domU
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: xen/privcmd: restrict usage in unprivileged domU The Xen privcmd driver allows to issue arbitrary hypercalls from user space processes. This is normally no problem, as access is usually limited to root and the hypervisor will deny any hypercalls affecting other domains. In case the guest is booted using secure boot, however, the privcmd driver would be enabling a root user process to modify e.g. kernel memory contents, thus breaking the secure boot feature. The only known case where an unprivileged domU is really needing to use the privcmd driver is the case when it is acting as the device model for another guest. In this case all hypercalls issued via the privcmd driver will target that other guest. Fortunately the privcmd driver can already be locked down to allow only hypercalls targeting a specific domain, but this mode can be activated from user land only today. The target domain can be obtained from Xenstore, so when not running in dom0 restrict the privcmd driver to that target domain from the beginning, resolving the potential problem of breaking secure boot. This is XSA-482 --- V2: - defer reading from Xenstore if Xenstore isn't ready yet (Jan Beulich) - wait in open() if target domain isn't known yet - issue message in case no target domain found (Jan Beulich)
Source: CVE Program / CVE List V5
CVSS Information
CVSS:3.1/AV:L/AC:L/PR:H/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
Vulnerability Title
Linux kernel 安全漏洞
Source: CNNVD (China National Vulnerability Database)
Vulnerability Description
Linux kernel是美国Linux基金会的开源操作系统Linux所使用的内核。 Linux kernel存在安全漏洞，该漏洞源于xen/privcmd驱动在非特权域中的使用限制不足，可能导致破坏安全启动功能。
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 1c5de1939c204bde9cce87f4eb3d26e9f9eb732b ~ 4eb245ff0d33b618e097a2c23de5df56d4ad6969 -
Linux Linux 2.6.37 -

II. Public POCs for CVE-2026-31788

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III. Intelligence Information for CVE-2026-31788

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Patches & Fixes for CVE-2026-31788 (6)

Same Patch Batch · Linux · 2026-03-25 · 116 CVEs total

CVE-2026-23395 8.8 HIGH Bluetooth: L2CAP: Fix accepting multiple L2CAP_ECRED_CONN_REQ
CVE-2026-23280 7.8 HIGH accel/amdxdna: Prevent ubuf size overflow
CVE-2026-23393 7.8 HIGH bridge: cfm: Fix race condition in peer_mep deletion
CVE-2026-23392 7.8 HIGH netfilter: nf_tables: release flowtable after rcu grace period on error
CVE-2026-23391 7.8 HIGH netfilter: xt_CT: drop pending enqueued packets on template removal
CVE-2026-23383 7.8 HIGH bpf, arm64: Force 8-byte alignment for JIT buffer to prevent atomic tearing
CVE-2026-23378 7.8 HIGH net/sched: act_ife: Fix metalist update behavior
CVE-2026-23372 7.8 HIGH nfc: rawsock: cancel tx_work before socket teardown
CVE-2026-23351 7.8 HIGH netfilter: nft_set_pipapo: split gc into unlink and reclaim phase
CVE-2026-23350 7.8 HIGH drm/xe/queue: Call fini on exec queue creation fail
CVE-2026-23340 7.8 HIGH net: sched: avoid qdisc_reset_all_tx_gt() vs dequeue race for lockless qdiscs
CVE-2026-23336 7.8 HIGH wifi: cfg80211: cancel rfkill_block work in wiphy_unregister()
CVE-2026-23317 7.8 HIGH drm/vmwgfx: Return the correct value in vmw_translate_ptr functions
CVE-2026-23306 7.8 HIGH scsi: pm8001: Fix use-after-free in pm8001_queue_command()
CVE-2026-23288 7.8 HIGH accel/amdxdna: Fix out-of-bounds memset in command slot handling
CVE-2026-23364 7.4 HIGH ksmbd: Compare MACs in constant time
CVE-2026-23294 7.0 HIGH bpf: Fix race in devmap on PREEMPT_RT
CVE-2026-23369 i2c: i801: Revert "i2c: i801: replace acpi_lock with I2C bus lock"
CVE-2026-23360 nvme: fix admin queue leak on controller reset
CVE-2026-23363 wifi: mt76: mt7925: Fix possible oob access in mt7925_mac_write_txwi_80211()

Showing top 20 of 116 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux

V. Comments for CVE-2026-31788

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