Is CVE-2021-47591 in the CISA KEV catalog?

No. CVE-2021-47591 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-47591?

CVE-2021-47591 has a CVSS v3 base score of 5.5 (MEDIUM).

What is the EPSS score for CVE-2021-47591?

CVE-2021-47591 has an EPSS score of 0.21% (11th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-47591?

Upgrade linux on debian 12 to 5.15.15-1 or later.

CVE & CISA-KEV Catalog

CVE-2021-47591

MEDIUM

5.5

CVSS v3

NVD

Description

In the Linux kernel, the following vulnerability has been resolved: mptcp: remove tcp ulp setsockopt support TCP_ULP setsockopt cannot be used for mptcp because its already used internally to plumb subflow (tcp) sockets to the mptcp layer. syzbot managed to trigger a crash for mptcp connections that are in fallback mode: KASAN: null-ptr-deref in range [0x0000000000000020-0x0000000000000027] CPU: 1 PID: 1083 Comm: syz-executor.3 Not tainted 5.16.0-rc2-syzkaller #0 RIP: 0010:tls_build_proto net/tls/tls_main.c:776 [inline] [..] __tcp_set_ulp net/ipv4/tcp_ulp.c:139 [inline] tcp_set_ulp+0x428/0x4c0 net/ipv4/tcp_ulp.c:160 do_tcp_setsockopt+0x455/0x37c0 net/ipv4/tcp.c:3391 mptcp_setsockopt+0x1b47/0x2400 net/mptcp/sockopt.c:638 Remove support for TCP_ULP setsockopt.

CWE-476NULL Pointer Dereference

How to fix

Remediation Available

linuxDebian

Fixed in:5.15.15-1CVE-2021-47591

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 RequiredLow

User InteractionNone

ScopeUnchanged

Impact

ConfidentialityNone

IntegrityNone

AvailabilityHigh

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

Exploit Intelligence

0.21%probability of exploitation in 30 days

11thpercentile

Low risk: more likely to be exploited than 11% of all known CVEs.

References

Patch2

Related Vulnerabilities

Other CWE-476 (NULL Pointer Dereference) vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2023-21758	High	7.5	92%	-	Fix
CVE-2023-21547	High	7.5	88%	-	Fix
CVE-2014-3470	Medium	4.3	86%	-	Fix
CVE-2021-44224	High	8.2	82%	-	Fix
CVE-2016-0742	High	7.5	82%	-	Fix
CVE-2009-1386	Medium	5.0	80%	-	Fix

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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 2024-11-21.