# CVE-2021-47647: clk: qcom: ipq8074: fix PCI-E clock oops > A missing clock parent definition in the Qualcomm IPQ8074 driver causes a kernel panic, leading to a denial of service on affected devices. - **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:** 26 Feb 2025 - **Updated:** 11 May 2026 - **Also known as:** DEBIAN-CVE-2021-47647, GHSA-wx79-2q2c-86qm, UBUNTU-CVE-2021-47647 ## What is CVE-2021-47647? CVE-2021-47647 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 2025. 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: clk: qcom: ipq8074: fix PCI-E clock oops Fix PCI-E clock related kernel oops that are caused by a missing clock parent. pcie0_rchng_clk_src has num_parents set to 2 but only one parent is actually set via parent_hws, it should also have "XO" defined. This will cause the kernel to panic on a NULL pointer in clk_core_get_parent_by_index(). So, to fix this utilize clk_parent_data to provide gcc_xo_gpll0 parent data. Since there is already an existing static const char * const gcc_xo_gpll0[] used to provide the same parents via parent_names convert those users to clk_parent_data as well. Without this earlycon is needed to even catch the OOPS as it will reset the board before serial is initialized with the following: [ 0.232279] Unable to handle kernel paging request at virtual address 0000a00000000000 [ 0.232322] Mem abort info: [ 0.239094] ESR = 0x96000004 [ 0.241778] EC = 0x25: DABT (current EL), IL = 32 bits [ 0.244908] SET = 0, FnV = 0 [ 0.250377] EA = 0, S1PTW = 0 [ 0.253236] FSC = 0x04: level 0 translation fault [ 0.256277] Data abort info: [ 0.261141] ISV = 0, ISS = 0x00000004 [ 0.264262] CM = 0, WnR = 0 [ 0.267820] [0000a00000000000] address between user and kernel address ranges [ 0.270954] Internal error: Oops: 96000004 [#1] SMP [ 0.278067] Modules linked in: [ 0.282751] CPU: 1 PID: 1 Comm: swapper/0 Not tainted 5.15.10 #0 [ 0.285882] Hardware name: Xiaomi AX3600 (DT) [ 0.292043] pstate: 20400005 (nzCv daif +PAN -UAO -TCO -DIT -SSBS BTYPE=--) [ 0.296299] pc : clk_core_get_parent_by_index+0x68/0xec [ 0.303067] lr : __clk_register+0x1d8/0x820 [ 0.308273] sp : ffffffc01111b7d0 [ 0.312438] x29: ffffffc01111b7d0 x28: 0000000000000000 x27: 0000000000000040 [ 0.315919] x26: 0000000000000002 x25: 0000000000000000 x24: ffffff8000308800 [ 0.323037] x23: ffffff8000308850 x22: ffffff8000308880 x21: ffffff8000308828 [ 0.330155] x20: 0000000000000028 x19: ffffff8000309700 x18: 0000000000000020 [ 0.337272] x17: 000000005cc86990 x16: 0000000000000004 x15: ffffff80001d9d0a [ 0.344391] x14: 0000000000000000 x13: 0000000000000000 x12: 0000000000000006 [ 0.351508] x11: 0000000000000003 x10: 0101010101010101 x9 : 0000000000000000 [ 0.358626] x8 : 7f7f7f7f7f7f7f7f x7 : 6468626f5e626266 x6 : 17000a3a403c1b06 [ 0.365744] x5 : 061b3c403a0a0017 x4 : 0000000000000000 x3 : 0000000000000001 [ 0.372863] x2 : 0000a00000000000 x1 : 0000000000000001 x0 : ffffff8000309700 [ 0.379982] Call trace: [ 0.387091] clk_core_get_parent_by_index+0x68/0xec [ 0.389351] __clk_register+0x1d8/0x820 [ 0.394210] devm_clk_hw_register+0x5c/0xe0 [ 0.398030] devm_clk_register_regmap+0x44/0x8c [ 0.402198] qcom_cc_really_probe+0x17c/0x1d0 [ 0.406711] qcom_cc_probe+0x34/0x44 [ 0.411224] gcc_ipq8074_probe+0x18/0x30 [ 0.414869] platform_probe+0x68/0xe0 [ 0.418776] really_probe.part.0+0x9c/0x30c [ 0.422336] __driver_probe_device+0x98/0x144 [ 0.426329] driver_probe_device+0x44/0x11c [ 0.430842] __device_attach_driver+0xb4/0x120 [ 0.434836] bus_for_each_drv+0x68/0xb0 [ 0.439349] __device_attach+0xb0/0x170 [ 0.443081] device_initial_probe+0x14/0x20 [ 0.446901] bus_probe_device+0x9c/0xa4 [ 0.451067] device_add+0x35c/0x834 [ 0.454886] of_device_add+0x54/0x64 [ 0.458360] of_platform_device_create_pdata+0xc0/0x100 [ 0.462181] of_platform_bus_create+0x114/0x370 [ 0.467128] of_platform_bus_create+0x15c/0x370 [ 0.471641] of_platform_populate+0x50/0xcc [ 0.476155] of_platform_default_populate_init+0xa8/0xc8 [ 0.480324] do_one_initcall+0x50/0x1b0 [ 0.485877] kernel_init_freeable+0x234/0x29c [ 0.489436] kernel_init+0x24/0x120 [ 0.493948] ret_from_fork+0x10/0x20 [ 0.497253] Code: d50323bf d65f03c0 f94002a2 b4000302 (f9400042) [ 0.501079] ---[ end trace 4ca7e1129da2abce ]--- Weakness: CWE-476 (NULL Pointer Dereference) ## Which versions are affected by CVE-2021-47647? It affects 1 product. Products: Linux kernel. ## How do I fix CVE-2021-47647? Apply the vendor's patch. ## Is CVE-2021-47647 being exploited? There is no known exploitation of CVE-2021-47647 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-2021-47647 and fix it if it is affected. What it is: CVE-2021-47647 is a medium-severity vulnerability in Linux kernel, published on 26 Feb 2025. 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-2021-47647 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-2021-47647/ (Markdown: https://insights.sbomify.com/CVE-2021-47647/index.md) ``` ## Sources - CVE record: https://www.cve.org/CVERecord?id=CVE-2021-47647 - NVD: https://nvd.nist.gov/vuln/detail/CVE-2021-47647 - OSV: https://osv.dev/vulnerability/CVE-2021-47647 --- From sbomify Insights: https://insights.sbomify.com/CVE-2021-47647/ Summaries are generated and may contain mistakes; the official description above is the record.