Is CVE-2021-4439 in the CISA KEV catalog?

No. CVE-2021-4439 is not currently on the CISA Known Exploited Vulnerabilities list.

What is the CVSS severity of CVE-2021-4439?

CVE-2021-4439 has a CVSS v3 base score of 7.8 (HIGH).

What is the EPSS score for CVE-2021-4439?

CVE-2021-4439 has an EPSS score of 0.24% (14th percentile), estimating the probability of exploitation in the next 30 days.

How do I fix CVE-2021-4439?

Upgrade linux on debian 11 to 5.10.84-1 or later.

CVE & CISA-KEV Catalog

CVE-2021-4439

HIGH

7.8

CVSS v3

NVD

Description

In the Linux kernel, the following vulnerability has been resolved: isdn: cpai: check ctr->cnr to avoid array index out of bound The cmtp_add_connection() would add a cmtp session to a controller and run a kernel thread to process cmtp. __module_get(THIS_MODULE); session->task = kthread_run(cmtp_session, session, "kcmtpd_ctr_%d", session->num); During this process, the kernel thread would call detach_capi_ctr() to detach a register controller. if the controller was not attached yet, detach_capi_ctr() would trigger an array-index-out-bounds bug. [ 46.866069][ T6479] UBSAN: array-index-out-of-bounds in drivers/isdn/capi/kcapi.c:483:21 [ 46.867196][ T6479] index -1 is out of range for type 'capi_ctr *[32]' [ 46.867982][ T6479] CPU: 1 PID: 6479 Comm: kcmtpd_ctr_0 Not tainted 5.15.0-rc2+ #8 [ 46.869002][ T6479] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS 1.14.0-2 04/01/2014 [ 46.870107][ T6479] Call Trace: [ 46.870473][ T6479] dump_stack_lvl+0x57/0x7d [ 46.870974][ T6479] ubsan_epilogue+0x5/0x40 [ 46.871458][ T6479] __ubsan_handle_out_of_bounds.cold+0x43/0x48 [ 46.872135][ T6479] detach_capi_ctr+0x64/0xc0 [ 46.872639][ T6479] cmtp_session+0x5c8/0x5d0 [ 46.873131][ T6479] ? __init_waitqueue_head+0x60/0x60 [ 46.873712][ T6479] ? cmtp_add_msgpart+0x120/0x120 [ 46.874256][ T6479] kthread+0x147/0x170 [ 46.874709][ T6479] ? set_kthread_struct+0x40/0x40 [ 46.875248][ T6479] ret_from_fork+0x1f/0x30 [ 46.875773][ T6479]

CWE-129

How to fix

Remediation Available

linuxDebian

Fixed in:5.10.84-1CVE-2021-4439

Fixed in:5.14.16-1CVE-2021-4439

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

ConfidentialityHigh

IntegrityHigh

AvailabilityHigh

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

Exploit Intelligence

0.24%probability of exploitation in 30 days

14thpercentile

Low risk: more likely to be exploited than 14% of all known CVEs.

References

Patch8

Related Vulnerabilities

Other CWE-129 vulnerabilities, ordered by exploit likelihood. View all

CVE	Severity	CVSS	EPSS	Exploited	Fix
CVE-2021-35592	Medium	6.3	51%	-	Fix
CVE-2021-35598	Medium	6.3	50%	-	Fix
CVE-2021-35594	Medium	6.3	50%	-	Fix
CVE-2022-35737	High	7.5	19%	-	Fix
CVE-2014-6317	High	7.1	18%	-	-
CVE-2023-40477	High	7.8	13%	-	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.