Linux KernelOperating system · Linux

CVE-2025-21821

MEDIUM · 5.5 CVSS v3.1 Published 2025-02-27

Fix available

A fix is available. Upgrade to 6.1.129 / 6.6.79 or later.

See remediation →

57/100

Remediation priority · Elevated

Zero-click Patch available

Official description

NVD · unedited

In the Linux kernel, the following vulnerability has been resolved: fbdev: omap: use threaded IRQ for LCD DMA When using touchscreen and framebuffer, Nokia 770 crashes easily with: BUG: scheduling while atomic: irq/144-ads7846/82/0x00010000 Modules linked in: usb_f_ecm g_ether usb_f_rndis u_ether libcomposite configfs omap_udc ohci_omap ohci_hcd CPU: 0 UID: 0 PID: 82 Comm: irq/144-ads7846 Not tainted 6.12.7-770 #2 Hardware name: Nokia 770 Call trace: unwind_backtrace from show_stack+0x10/0x14 show_stack from dump_stack_lvl+0x54/0x5c dump_stack_lvl from __schedule_bug+0x50/0x70 __schedule_bug from __schedule+0x4d4/0x5bc __schedule from schedule+0x34/0xa0 schedule from schedule_preempt_disabled+0xc/0x10 schedule_preempt_disabled from __mutex_lock.constprop.0+0x218/0x3b4 __mutex_lock.constprop.0 from clk_prepare_lock+0x38/0xe4 clk_prepare_lock from clk_set_rate+0x18/0x154 clk_set_rate from sossi_read_data+0x4c/0x168 sossi_read_data from hwa742_read_reg+0x5c/0x8c hwa742_read_reg from send_frame_handler+0xfc/0x300 send_frame_handler from process_pending_requests+0x74/0xd0 process_pending_requests from lcd_dma_irq_handler+0x50/0x74 lcd_dma_irq_handler from __handle_irq_event_percpu+0x44/0x130 __handle_irq_event_percpu from handle_irq_event+0x28/0x68 handle_irq_event from handle_level_irq+0x9c/0x170 handle_level_irq from generic_handle_domain_irq+0x2c/0x3c generic_handle_domain_irq from omap1_handle_irq+0x40/0x8c omap1_handle_irq from generic_handle_arch_irq+0x28/0x3c generic_handle_arch_irq from call_with_stack+0x1c/0x24 call_with_stack from __irq_svc+0x94/0xa8 Exception stack(0xc5255da0 to 0xc5255de8) 5da0: 00000001 c22fc620 00000000 00000000 c08384a8 c106fc00 00000000 c240c248 5dc0: c113a600 c3f6ec30 00000001 00000000 c22fc620 c5255df0 c22fc620 c0279a94 5de0: 60000013 ffffffff __irq_svc from clk_prepare_lock+0x4c/0xe4 clk_prepare_lock from clk_get_rate+0x10/0x74 clk_get_rate from uwire_setup_transfer+0x40/0x180 uwire_setup_transfer from spi_bitbang_transfer_one+0x2c/0x9c spi_bitbang_transfer_one from spi_transfer_one_message+0x2d0/0x664 spi_transfer_one_message from __spi_pump_transfer_message+0x29c/0x498 __spi_pump_transfer_message from __spi_sync+0x1f8/0x2e8 __spi_sync from spi_sync+0x24/0x40 spi_sync from ads7846_halfd_read_state+0x5c/0x1c0 ads7846_halfd_read_state from ads7846_irq+0x58/0x348 ads7846_irq from irq_thread_fn+0x1c/0x78 irq_thread_fn from irq_thread+0x120/0x228 irq_thread from kthread+0xc8/0xe8 kthread from ret_from_fork+0x14/0x28 As a quick fix, switch to a threaded IRQ which provides a stable system.

Technical summary

dbcve analysis

A detailed technical summary for this CVE is being prepared.

Affected products & versions

NVD · CPE data

Linux KernelOperating system

Affected:< 6.1.129>= 6.2, < 6.6.79>= 6.7, < 6.12.16>= 6.13, < 6.13.4

CVSS breakdown

From the vector

Attack vector: Local
Complexity: Low
Privileges: Low
User interaction: None
Scope: Unchanged
Confidentiality: None
Integrity: None
Availability: High

CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H

Remediation

dbcve · scoped

Upgrade available Upgrade to 6.1.129 / 6.6.79 / 6.12.16 or later

Fixed in 6.1.1296.6.796.12.16

Vendor patch git.kernel.org →

Recommended fix High confidence

6.12.16 or later (or 6.13.4+, 6.6.79+)

Identify the current kernel version using `uname -r` or `cat /proc/version`
Upgrade the Linux kernel to version 6.12.16 or later (alternatively: 6.6.79+, 6.13.4+)
Reboot the system to load the patched kernel

Caveat Kernel upgrades may introduce subtle changes; test in staging if possible

Generated from the published advisory — verify against the referenced sources before acting.

We can perform the upgrade in your staging environment and verify nothing breaks — typical engagement from $1,600. Get the upgrade done

Scan for this in your stack

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References

Primary sources

Practitioner notes

Contributed

Peer-ranked notes from engineers who’ve handled CVE-2025-21821 in production — separate from our analysis above.

Notes0 Guidelines

Know something about CVE-2025-21821?

The advisory tells you what broke. It rarely tells you what actually worked. If you’ve dealt with this one, that detail is what the next engineer is searching for.

The version that genuinely resolved it — not the one the vendor claimed
A config change or rule that shut the vector down
A gotcha in the upgrade path that cost you an afternoon

No notes yet

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What this is

A place for practitioners to share what actually worked: a mitigation you’ve tested, a configuration change, a version- or environment-specific caveat, or a link to a verified patch. The most useful notes rise to the top as peers upvote them, so the signal stays high.

What belongs here

Verified mitigations, workarounds, and config changes
Version or environment caveats, and links to real fixes
No weaponised exploit code, or anything meant to cause harm
No spam, self-promotion, credentials, or personal data

At a glance

A fix existsUpgrade to 6.1.129 / 6.6.79 or later

Severity 5.5 Medium

Exploit likelihood EPSS, next 30 days 0.2%

Affects: Linux Kernel

Remediation

Need this fixed?

Get a fix

Estimated effortfrom ~9 hrs

ComplexityModerate

Typical engagementfrom $1,600

What a fix involves

We scope it with you and confirm a fixed quote
A specialist builds a reviewed fix
You deploy it to staging first
Optional re-test once it’s live

We specialise in CVE remediation. Send your environment and we’ll scope CVE-2025-21821 and return a fixed quote.

You’ll deal with our team directly and deploy the reviewed fix to staging first — never straight to production.

Official description Straight from the sourceThe vendor's or NVD's own wording, published unedited. Authoritative, but often terse — it says what broke, rarely what to do.

Technical summary Written by usOur analysis, written from the advisory, the CVSS vector and the affected-version data. It adds context the advisory leaves out, and never invents facts that are not in the source.

Affected products & versions What the vendor confirmedThe version ranges the vendor confirmed as vulnerable. If your version sits inside a range here, treat yourself as exposed until you have upgraded.

CVSS breakdown How the score is builtThe industry scoring standard. It rates how the flaw is reached, what it takes to exploit, and what an attacker gains — the score is derived from those, not the other way round.

Remediation Closing itWhat it takes to close this. Where a vendor fix exists we point at it; where none exists we say so plainly, and can build one. Effort estimates are scoped from the advisory, not from your codebase.

Scan for this in your stack

References Go to the primary sourcePrimary sources — vendor advisories, patches and trackers. Where our summary and a reference disagree, the reference wins.

Practitioner notes

No notes yet

Official description

Technical summary

Affected products & versions

CVSS breakdown

Remediation

References