# CVE-2026-43087: pinctrl: mcp23s08: Disable all pin interrupts during probe > A null pointer dereference in the MCP23S08 pinctrl driver during probe can cause a kernel crash if pin interrupts are enabled. - **Severity:** Medium 5.5 (`CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H`) - **Exploited in the wild:** Not known - **Login needed:** Any signed-in user - **Attackable:** Local or same network only - **Victim action needed:** Not needed - **Fix available:** Yes - **Published:** 6 May 2026 - **Updated:** 11 May 2026 - **Also known as:** DEBIAN-CVE-2026-43087, GHSA-wq7v-qv29-77h9, UBUNTU-CVE-2026-43087 ## What is CVE-2026-43087? CVE-2026-43087 is a medium-severity vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, with no action from the victim. ### Official description In the Linux kernel, the following vulnerability has been resolved: pinctrl: mcp23s08: Disable all pin interrupts during probe A chip being probed may have the interrupt-on-change feature enabled on some of its pins, for example after a reboot. This can cause the chip to generate interrupts for pins that don't have a registered nested handler, which leads to a kernel crash such as below: [ 7.928897] Unable to handle kernel read from unreadable memory at virtual address 00000000000000ac [ 7.932314] Mem abort info: [ 7.935081] ESR = 0x0000000096000004 [ 7.938808] EC = 0x25: DABT (current EL), IL = 32 bits [ 7.944094] SET = 0, FnV = 0 [ 7.947127] EA = 0, S1PTW = 0 [ 7.950247] FSC = 0x04: level 0 translation fault [ 7.955101] Data abort info: [ 7.957961] ISV = 0, ISS = 0x00000004, ISS2 = 0x00000000 [ 7.963421] CM = 0, WnR = 0, TnD = 0, TagAccess = 0 [ 7.968447] GCS = 0, Overlay = 0, DirtyBit = 0, Xs = 0 [ 7.973734] user pgtable: 4k pages, 48-bit VAs, pgdp=00000000089b7000 [ 7.980148] [00000000000000ac] pgd=0000000000000000, p4d=0000000000000000 [ 7.986913] Internal error: Oops: 0000000096000004 [#1] SMP [ 7.992545] Modules linked in: [ 8.073678] CPU: 0 UID: 0 PID: 81 Comm: irq/18-4-0025 Not tainted 7.0.0-rc6-gd2b5a1f931c8-dirty #199 [ 8.073689] Hardware name: Khadas VIM3 (DT) [ 8.073692] pstate: 604000c5 (nZCv daIF +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 8.094639] pc : _raw_spin_lock_irq+0x40/0x80 [ 8.098970] lr : handle_nested_irq+0x2c/0x168 [ 8.098979] sp : ffff800082b2bd20 [ 8.106599] x29: ffff800082b2bd20 x28: ffff800080107920 x27: ffff800080104d88 [ 8.106611] x26: ffff000003298080 x25: 0000000000000001 x24: 000000000000ff00 [ 8.113707] x23: 0000000000000001 x22: 0000000000000000 x21: 000000000000000e [ 8.120850] x20: 0000000000000000 x19: 00000000000000ac x18: 0000000000000000 [ 8.135046] x17: 0000000000000000 x16: 0000000000000000 x15: 0000000000000000 [ 8.135062] x14: ffff800081567ea8 x13: ffffffffffffffff x12: 0000000000000000 [ 8.135070] x11: 00000000000000c0 x10: 0000000000000b60 x9 : ffff800080109e0c [ 8.135078] x8 : 1fffe0000069dbc1 x7 : 0000000000000001 x6 : ffff0000034ede00 [ 8.135086] x5 : 0000000000000000 x4 : ffff0000034ede08 x3 : 0000000000000001 [ 8.163460] x2 : 0000000000000000 x1 : 0000000000000001 x0 : 00000000000000ac [ 8.170560] Call trace: [ 8.180094] _raw_spin_lock_irq+0x40/0x80 (P) [ 8.184443] mcp23s08_irq+0x248/0x358 [ 8.184462] irq_thread_fn+0x34/0xb8 [ 8.184470] irq_thread+0x1a4/0x310 [ 8.195093] kthread+0x13c/0x150 [ 8.198309] ret_from_fork+0x10/0x20 [ 8.201850] Code: d65f03c0 d2800002 52800023 f9800011 (885ffc01) [ 8.207931] ---[ end trace 0000000000000000 ]--- This issue has always been present, but has been latent until commit "f9f4fda15e72" ("pinctrl: mcp23s08: init reg_defaults from HW at probe and switch cache type"), which correctly removed reg_defaults from the regmap and as a side effect changed the behavior of the interrupt handler so that the real value of the MCP_GPINTEN register is now being read from the chip instead of using a bogus 0 default value; a non-zero value for this register can trigger the invocation of a nested handler which may not exist (yet). Fix this issue by disabling all pin interrupts during initialization. ## Which versions are affected by CVE-2026-43087? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2026-43087? Apply the vendor's patch. ## Is CVE-2026-43087 being exploited? There is no known exploitation of CVE-2026-43087 in the wild and no public exploit code. ## Other vulnerabilities in Linux kernel - [CVE-2026-53266](https://insights.sbomify.com/CVE-2026-53266/): Linux Kernel Out-of-Bounds Write (high 8.8, exploited in the wild) - [CVE-2013-6282](https://insights.sbomify.com/CVE-2013-6282/): Linux Kernel Improper Input Validation (high 8.8, exploited in the wild) - [CVE-2022-0185](https://insights.sbomify.com/CVE-2022-0185/): Linux Kernel Heap-Based Buffer Overflow (high 8.4, exploited in the wild) - [CVE-2013-2094](https://insights.sbomify.com/CVE-2013-2094/): Linux Kernel Privilege Escalation (high 8.4, exploited in the wild) - [CVE-2026-53362](https://insights.sbomify.com/CVE-2026-53362/): Linux Kernel Unspecified (high 7.8, exploited in the wild) ## Fix prompt for AI coding agents ```text Check this codebase for CVE-2026-43087 and fix it if it is affected. What it is: CVE-2026-43087 is a medium-severity vulnerability in Linux kernel, published on 6 May 2026. It can only be exploited from the same machine or local network, with no action from the victim. Exploitation: There is no known exploitation of CVE-2026-43087 in the wild and no public exploit code. Affected product: Linux kernel. No package-level version data is available, so check the vendor advisory linked from the reference page. Task: 1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies. 2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it. 3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead. 4. Run the tests and summarise what changed and why. 5. If nothing in the project is affected, say so and change nothing. Reference: https://insights.sbomify.com/CVE-2026-43087/ (Markdown: https://insights.sbomify.com/CVE-2026-43087/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2026-43087 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-43087 - OSV: https://osv.dev/vulnerability/CVE-2026-43087 --- From sbomify Insights: https://insights.sbomify.com/CVE-2026-43087/ Summaries are generated and may contain mistakes; the official description above is the record.