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CVE-2025-21976— fbdev: hyperv_fb: Allow graceful removal of framebuffer

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fbdev hyperv_fb模块在移除帧缓冲时未正确处理。

CVSS 7.8 · High EPSS 0.26% · P17

Affected Version Matrix 10

VendorProduct Version RangeStatus
Linux Linux 68a2d20b79b105f02dcbc52c211d7e62f98996b7< b1a86a5ab0d44160534f495a3630646092d98e27 affected
68a2d20b79b105f02dcbc52c211d7e62f98996b7< 4545e2aa121aea304d33903099c03e29ed4fe50a affected
68a2d20b79b105f02dcbc52c211d7e62f98996b7< a7b583dc99c6cf4a96877017be1d08247e1ef2c7 affected
68a2d20b79b105f02dcbc52c211d7e62f98996b7< ea2f45ab0e53b255f72c85ccd99e2b394fc5fceb affected
3.10 affected
< 3.10 unaffected
6.6.160≤ 6.6.* unaffected
6.12.20≤ 6.12.* unaffected
… +2 more rows
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I. Basic Information for CVE-2025-21976

Vulnerability Information
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Vulnerability Title
fbdev: hyperv_fb: Allow graceful removal of framebuffer
Source: CVE Program / CVE List V5
Vulnerability Description
In the Linux kernel, the following vulnerability has been resolved: fbdev: hyperv_fb: Allow graceful removal of framebuffer When a Hyper-V framebuffer device is unbind, hyperv_fb driver tries to release the framebuffer forcefully. If this framebuffer is in use it produce the following WARN and hence this framebuffer is never released. [ 44.111220] WARNING: CPU: 35 PID: 1882 at drivers/video/fbdev/core/fb_info.c:70 framebuffer_release+0x2c/0x40 < snip > [ 44.111289] Call Trace: [ 44.111290] <TASK> [ 44.111291] ? show_regs+0x6c/0x80 [ 44.111295] ? __warn+0x8d/0x150 [ 44.111298] ? framebuffer_release+0x2c/0x40 [ 44.111300] ? report_bug+0x182/0x1b0 [ 44.111303] ? handle_bug+0x6e/0xb0 [ 44.111306] ? exc_invalid_op+0x18/0x80 [ 44.111308] ? asm_exc_invalid_op+0x1b/0x20 [ 44.111311] ? framebuffer_release+0x2c/0x40 [ 44.111313] ? hvfb_remove+0x86/0xa0 [hyperv_fb] [ 44.111315] vmbus_remove+0x24/0x40 [hv_vmbus] [ 44.111323] device_remove+0x40/0x80 [ 44.111325] device_release_driver_internal+0x20b/0x270 [ 44.111327] ? bus_find_device+0xb3/0xf0 Fix this by moving the release of framebuffer and assosiated memory to fb_ops.fb_destroy function, so that framebuffer framework handles it gracefully. While we fix this, also replace manual registrations/unregistration of framebuffer with devm_register_framebuffer.
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fbdev hyperv_fb模块在移除帧缓冲时未正确处理。
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 68a2d20b79b105f02dcbc52c211d7e62f98996b7 ~ b1a86a5ab0d44160534f495a3630646092d98e27 -
Linux Linux 3.10 -

II. Public POCs for CVE-2025-21976

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III. Intelligence Information for CVE-2025-21976

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Patches & Fixes for CVE-2025-21976 (2)

Other References for CVE-2025-21976 (1)

Same Patch Batch · Linux · 2025-04-01 · 93 CVEs total

CVE-2025-21954 9.8 CRITICAL netmem: prevent TX of unreadable skbs
CVE-2025-21927 9.8 CRITICAL nvme-tcp: fix potential memory corruption in nvme_tcp_recv_pdu()
CVE-2025-21955 8.8 HIGH ksmbd: prevent connection release during oplock break notification
CVE-2025-21946 8.8 HIGH ksmbd: fix out-of-bounds in parse_sec_desc()
CVE-2025-21945 8.8 HIGH ksmbd: fix use-after-free in smb2_lock
CVE-2025-21969 8.8 HIGH Bluetooth: L2CAP: Fix slab-use-after-free Read in l2cap_send_cmd
CVE-2025-21967 8.8 HIGH ksmbd: fix use-after-free in ksmbd_free_work_struct
CVE-2025-21972 8.8 HIGH net: mctp: unshare packets when reassembling
CVE-2025-21947 8.1 HIGH ksmbd: fix type confusion via race condition when using ipc_msg_send_request
CVE-2025-21926 7.8 HIGH net: gso: fix ownership in __udp_gso_segment
CVE-2025-21971 7.8 HIGH net_sched: Prevent creation of classes with TC_H_ROOT
CVE-2025-21899 7.8 HIGH tracing: Fix bad hist from corrupting named_triggers list
CVE-2025-21979 7.8 HIGH wifi: cfg80211: cancel wiphy_work before freeing wiphy
CVE-2025-21901 7.8 HIGH RDMA/bnxt_re: Add sanity checks on rdev validity
CVE-2025-21966 7.8 HIGH dm-flakey: Fix memory corruption in optional corrupt_bio_byte feature
CVE-2025-21965 7.8 HIGH sched_ext: Validate prev_cpu in scx_bpf_select_cpu_dfl()
CVE-2025-21934 7.8 HIGH rapidio: fix an API misues when rio_add_net() fails
CVE-2025-21939 7.8 HIGH drm/xe/hmm: Don't dereference struct page pointers without notifier lock
CVE-2025-21958 7.8 HIGH Revert "openvswitch: switch to per-action label counting in conntrack"
CVE-2025-21949 7.8 HIGH LoongArch: Set hugetlb mmap base address aligned with pmd size

Showing top 20 of 93 CVEs. View all on vendor page &rarr; →

IV. Related Vulnerabilities

Same product: Linux
Same vendor: Linux