Out-of-Bounds Write in Linux kernel (CVE-2021-47535)
Summary
Out-of-bounds write in Linux kernel (CVE-2021-47535). Successful exploitation can lead to full system takeover.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
drm/msm/a6xx: Allocate enough space for GMU registers
In commit 142639a52a01 ("drm/msm/a6xx: fix crashstate capture for
A650") we changed a6xx_get_gmu_registers() to read 3 sets of
registers. Unfortunately, we didn't change the memory allocation for
the array. That leads to a KASAN warning (this was on the chromeos-5.4
kernel, which has the problematic commit backported to it):
BUG: KASAN: slab-out-of-bounds in _a6xx_get_gmu_registers+0x144/0x430
Write of size 8 at addr ffffff80c89432b0 by task A618-worker/209
CPU: 5 PID: 209 Comm: A618-worker Tainted: G W 5.4.156-lockdep #22
Hardware name: Google Lazor Limozeen without Touchscreen (rev5 - rev8) (DT)
Call trace:
dump_backtrace+0x0/0x248
show_stack+0x20/0x2c
dump_stack+0x128/0x1ec
print_address_description+0x88/0x4a0
__kasan_report+0xfc/0x120
kasan_report+0x10/0x18
__asan_report_store8_noabort+0x1c/0x24
_a6xx_get_gmu_registers+0x144/0x430
a6xx_gpu_state_get+0x330/0x25d4
msm_gpu_crashstate_capture+0xa0/0x84c
recover_worker+0x328/0x838
kthread_worker_fn+0x32c/0x574
kthread+0x2dc/0x39c
ret_from_fork+0x10/0x18
Allocated by task 209:
__kasan_kmalloc+0xfc/0x1c4
kasan_kmalloc+0xc/0x14
kmem_cache_alloc_trace+0x1f0/0x2a0
a6xx_gpu_state_get+0x164/0x25d4
msm_gpu_crashstate_capture+0xa0/0x84c
recover_worker+0x328/0x838
kthread_worker_fn+0x32c/0x574
kthread+0x2dc/0x39c
ret_f…
Source: NIST National Vulnerability Database NVD
Auto-generated summary
Assembled by SecPulse from the source data (CVSS, CWE, affected versions) using templates — no AI involved. Check the original description and references below for exact details.
A vulnerability tracked as CVE-2021-47535 has been found in Linux kernel.
Successful exploitation can lead to full system takeover. CVSS score: 7.8/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2021-47535" on the vendor's site.
CVE-2021-47535 (Linux kernel) — CWE-787 / CVSS v3 7.8
Attack vector: local / no user interaction
Plan: 1) Audit SBOM/dependencies, 2) Stage→prod upgrade, 3) Add WAF/proxy monitoring on affected endpoints, 4) Hunt IOCs in logs.
Refs: see the GHSA / vendor advisory / patched release linked on this page.
Out-of-bounds write (CWE-787) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.8/10). Successful exploitation can lead to full system takeover.
Update to the patched release per vendor advisory.
Until the patch is applied: disable the affected feature, apply WAF rules, or restrict access via network ACLs.
Search webserver/proxy logs for unusual request patterns matching this CVE's known IOCs. Audit SBOM/dependencies to find affected services.
Response actions
Concrete steps and command examples for SOC/SRE teams to execute in order
-
1Identify exposure identify
Audit SBOM/dependencies for affected components.資産台帳・SBOM・依存マニフェストで Linux kernel を使っているサービスとバージョンを洗い出す。
-
2Post-deployment verification verify
Confirm patched version is live in productionパッチ適用後、ステージングで PoC または同等の悪用パターンを再現して脆弱性が閉じたことを確認。本番ではアクセスログ・WAF でアラート再発が無いか継続監視。
Fix status by distribution
Fixed packages published by each distribution for this CVE
- Debian DEBIAN-CVE-2021-47535 linux Fixed in: 5.15.15-1
- Ubuntu UBUNTU-CVE-2021-47535 linux-hwe-edge
References
- patch git.kernel.org
- patch git.kernel.org
- patch git.kernel.org