Is CVE-2021-47242 in the CISA KEV catalog?

No. CVE-2021-47242 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-47242?

CVE-2021-47242 has a CVSS v3 base score of 7.8 (HIGH).

What is the EPSS score for CVE-2021-47242?

CVE-2021-47242 has an EPSS score of 0.19% (8th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-47242?

Upgrade linux kernel to 5.12.13 or later.

CVE & CISA-KEV Catalog

CVE-2021-47242

HIGH

7.8

CVSS v3

NVD

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: fix soft lookup in subflow_error_report() Maxim reported a soft lookup in subflow_error_report(): watchdog: BUG: soft lockup - CPU#0 stuck for 22s! [swapper/0:0] RIP: 0010:native_queued_spin_lock_slowpath RSP: 0018:ffffa859c0003bc0 EFLAGS: 00000202 RAX: 0000000000000101 RBX: 0000000000000001 RCX: 0000000000000000 RDX: ffff9195c2772d88 RSI: 0000000000000000 RDI: ffff9195c2772d88 RBP: ffff9195c2772d00 R08: 00000000000067b0 R09: c6e31da9eb1e44f4 R10: ffff9195ef379700 R11: ffff9195edb50710 R12: ffff9195c2772d88 R13: ffff9195f500e3d0 R14: ffff9195ef379700 R15: ffff9195ef379700 FS: 0000000000000000(0000) GS:ffff91961f400000(0000) knlGS:0000000000000000 CS: 0010 DS: 0000 ES: 0000 CR0: 0000000080050033 CR2: 000000c000407000 CR3: 0000000002988000 CR4: 00000000000006f0 Call Trace: <IRQ> _raw_spin_lock_bh subflow_error_report mptcp_subflow_data_available __mptcp_move_skbs_from_subflow mptcp_data_ready tcp_data_queue tcp_rcv_established tcp_v4_do_rcv tcp_v4_rcv ip_protocol_deliver_rcu ip_local_deliver_finish __netif_receive_skb_one_core netif_receive_skb rtl8139_poll 8139too __napi_poll net_rx_action __do_softirq __irq_exit_rcu common_interrupt </IRQ> The calling function - mptcp_subflow_data_available() - can be invoked from different contexts: - plain ssk socket lock - ssk socket lock + mptcp_data_lock - ssk socket lock + mptcp_data_lock + msk socket lock. Since subflow_error_report() tries to acquire the mptcp_data_lock, the latter two call chains will cause soft lookup. This change addresses the issue moving the error reporting call to outer functions, where the held locks list is known and the we can acquire only the needed one.

CWE-667

How to fix

Remediation Available

linux kernelNVD

Affected:>= 5.11.12, < 5.12.13Fixed in:5.12.13CVE-2021-47242derived from NVD

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorLocal

Attack ComplexityLow

Privileges RequiredNone

User InteractionRequired

ScopeUnchanged

Impact

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.19%probability of exploitation in 30 days

8thpercentile

Low risk: more likely to be exploited than 8% of all known CVEs.

References

Patch2

Related Vulnerabilities

Other CWE-667 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2019-10072	High	7.5	73%	-	Fix
CVE-2002-1850	High	7.5	17%	-	Fix
CVE-2009-2699	High	7.5	14%	-	Fix
CVE-2004-0174	High	7.5	12%	-	-
CVE-2009-4272	High	7.5	11%	-	-
CVE-2020-24606	High	8.6	5.2%	-	Fix

Embed a live status badge for CVE-2021-47242

Markdown

[![CVE-2021-47242](https://tridentstack.com/cve/badge/CVE-2021-47242.svg)](https://tridentstack.com/cve/CVE-2021-47242)

HTML

<a href="https://tridentstack.com/cve/CVE-2021-47242"><img src="https://tridentstack.com/cve/badge/CVE-2021-47242.svg" alt="CVE-2021-47242"></a>

Find and fix vulnerabilities across your fleet

TridentStack Control continuously scans your Windows, macOS, and Linux fleet for known vulnerabilities, prioritizes them by severity and active exploitation, and patches them automatically.

Start free

This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2025-04-04.