Out-of-Bounds Read in Linux kernel (CVE-2021-47346)
Summary
Vulnerability in Linux kernel (CVE-2021-47346). Confidential information can be exposed externally.
Original description
The description as published by the source.
In the Linux kernel, the following vulnerability has been resolved:
coresight: tmc-etf: Fix global-out-of-bounds in tmc_update_etf_buffer()
commit 6f755e85c332 ("coresight: Add helper for inserting synchronization
packets") removed trailing '\0' from barrier_pkt array and updated the
call sites like etb_update_buffer() to have proper checks for barrier_pkt
size before read but missed updating tmc_update_etf_buffer() which still
reads barrier_pkt past the array size resulting in KASAN out-of-bounds
bug. Fix this by adding a check for barrier_pkt size before accessing
like it is done in etb_update_buffer().
BUG: KASAN: global-out-of-bounds in tmc_update_etf_buffer+0x4b8/0x698
Read of size 4 at addr ffffffd05b7d1030 by task perf/2629
Call trace:
dump_backtrace+0x0/0x27c
show_stack+0x20/0x2c
dump_stack+0x11c/0x188
print_address_description+0x3c/0x4a4
__kasan_report+0x140/0x164
kasan_report+0x10/0x18
__asan_report_load4_noabort+0x1c/0x24
tmc_update_etf_buffer+0x4b8/0x698
etm_event_stop+0x248/0x2d8
etm_event_del+0x20/0x2c
event_sched_out+0x214/0x6f0
group_sched_out+0xd0/0x270
ctx_sched_out+0x2ec/0x518
__perf_event_task_sched_out+0x4fc/0xe6c
__schedule+0x1094/0x16a0
preempt_schedule_irq+0x88/0x170
arm64_preempt_schedule_irq+0xf0/0x18c
el1_irq+0xe8/0x180
perf_event_exec+0x4d8/0x56c
setup_new_exec+0x204/0x400
load_elf_binary+0x72c/0x18c0
search_binary_handler+0x13c/0x420
load_script+0x500/0x6c4
search_binary_handler+0x13c/0x420…
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-2021-47346 has been found in Linux kernel.
Confidential information can be exposed externally. CVSS score: 7.1/10.
What to do: apply the vendor's official patched release.
If unsure, ask your IT team or search "Linux kernel CVE-2021-47346" on the vendor's site.
CVE-2021-47346 (Linux kernel) — CWE-125 / CVSS v3 7.1
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 read (CWE-125) exists in Linux kernel.
Check the vendor advisory for the affected versions of Linux kernel.
Severity: High (CVSS 7.1/10). Confidential information can be exposed externally.
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-2021-47346 linux Fixed in: 5.14.6-1
- Ubuntu UBUNTU-CVE-2021-47346 linux-azure Fixed in: 4.15.0-1123.136~14.04.1
References
- patch git.kernel.org
- patch git.kernel.org
- patch git.kernel.org
- patch git.kernel.org
- patch git.kernel.org
- patch git.kernel.org