CVE-2021-4173

Use After Free in vim/vim

6.8 MediumFix available

vim is vulnerable to Use After Free

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: Low
User interaction: Required

What an attacker can affect

Confidentiality: Low
Integrity: High
Availability: High

Exploit likelihood

1.76%Up 1.1 points since Dec 28, 2021

What each source reports

CVE List Score used 6.8

Use After Free in vim/vim

vim is vulnerable to Use After Free

Record: CVE-2021-4173
CVSS 3.0: 6.8 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H
Weakness: CWE-416
Updated: 2026-11-02

EUVDEUVD-2021-34035 6.8

vim is vulnerable to Use After Free

Record: EUVD-2021-34035
CVSS 3.0: 6.8 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H
Updated: 2026-11-03

GitHub AdvisoriesGHSA-h3r6-368v-w6xc 7.8

vim is vulnerable to Use After Free

vim is vulnerable to Use After Free

Record: GHSA-h3r6-368v-w6xc
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-416
Updated: 2026-11-02

NVD 7.8

vim is vulnerable to Use After Free

Record: CVE-2021-4173
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 3.0: 6.8 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H
CVSS 2.0: 6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness: CWE-416
Updated: 2026-11-03

OSVALPINE-CVE-2021-4173 7.8

vim is vulnerable to Use After Free

Record: ALPINE-CVE-2021-4173
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-03

OSVAZL-7084 7.8

CVE-2021-4173 affecting package vim for versions less than 8.2.4081-1

vim is vulnerable to Use After Free

Record: AZL-7084
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

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OSVBELL-CVE-2021-4173 7.8

CVE-2021-4173 does not affect BellSoft software

Record: BELL-CVE-2021-4173
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSV 7.8

vim is vulnerable to Use After Free

Record: CVE-2021-4173
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-04

OSVDEBIAN-CVE-2021-4173 7.8

vim is vulnerable to Use After Free

Record: DEBIAN-CVE-2021-4173
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-03

OSVUBUNTU-CVE-2021-4173 7.8

vim is vulnerable to Use After Free

Record: UBUNTU-CVE-2021-4173
CVSS 3.1: 7.8 HighCVSS:3.1/AV:L/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
CVSS 3.0: 6.8 MediumCVSS:3.0/AV:L/AC:L/PR:L/UI:R/S:U/C:L/I:H/A:H
Updated: 2026-11-02

OSVCLSA-2026-1777313322 No score

vim: Fix of 3 CVEs

CVE-2021-4173: fix double free in Vim9 nested :def function definition
CVE-2022-3352: fix use-after-free when SpellFileMissing autocmd deletes the current buffer during spell file loading
CVE-2022-2343: fix heap buffer overflow in ins_compl_add_infercase() when completing a long line with 'infercase' set

Record: CLSA-2026-1777313322
Updated: 2026-11-02

OSVCLSA-2026-1777323039 No score

vim: Fix of 3 CVEs

CVE-2021-4173: fix double free in Vim9 nested :def function definition
CVE-2022-3352: fix use-after-free when SpellFileMissing autocmd deletes the current buffer during spell file loading
CVE-2022-2343: fix heap buffer overflow in ins_compl_add_infercase() when completing a long line with 'infercase' set

Record: CLSA-2026-1777323039
Updated: 2026-11-02

OSVMGASA-2022-0015 No score

Updated vim packages fix security vulnerability

CWE-122 Heap-based Buffer Overflow (CVE-2021-4136) CWE-125 Out-of-bounds Read (CVE-2021-4166) CWE-416 Use After Free (CVE-2021-4173) CWE-416 Use After Free (CVE-2021-4187)

Record: MGASA-2022-0015
Updated: 2026-11-02

Affected products

Affected packages

Affected packages
Package	Affected	Fixed
`vim` Alpine:v3.12	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.13	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.14	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.15	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.16	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.17	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.18	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.19	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.20	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.21	before 8.2.4173-r0	8.2.4173-r0

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Affected packages
Package	Affected	Fixed
`vim` Alpine:v3.22	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.23	before 8.2.4173-r0	8.2.4173-r0
`vim` Alpine:v3.24	before 8.2.4173-r0	8.2.4173-r0
`vim` Azure Linux:2	before 8.2.4081-1	8.2.4081-1
`vim-X11` TuxCare:AlmaLinux:9.6 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_6.1.tuxcare.els11	2:8.2.2637-22.el9_6.1.tuxcare.els11
`vim-common` TuxCare:AlmaLinux:9.6 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_6.1.tuxcare.els11	2:8.2.2637-22.el9_6.1.tuxcare.els11
`vim-enhanced` TuxCare:AlmaLinux:9.6 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_6.1.tuxcare.els11	2:8.2.2637-22.el9_6.1.tuxcare.els11
`vim-filesystem` TuxCare:AlmaLinux:9.6 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_6.1.tuxcare.els11	2:8.2.2637-22.el9_6.1.tuxcare.els11
`vim-minimal` TuxCare:AlmaLinux:9.6 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_6.1.tuxcare.els11	2:8.2.2637-22.el9_6.1.tuxcare.els11
`vim-X11` TuxCare:AlmaLinux:9.2 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_1.1.tuxcare.els11	2:8.2.2637-22.el9_1.1.tuxcare.els11
`vim-common` TuxCare:AlmaLinux:9.2 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_1.1.tuxcare.els11	2:8.2.2637-22.el9_1.1.tuxcare.els11
`vim-enhanced` TuxCare:AlmaLinux:9.2 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_1.1.tuxcare.els11	2:8.2.2637-22.el9_1.1.tuxcare.els11
`vim-filesystem` TuxCare:AlmaLinux:9.2 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_1.1.tuxcare.els11	2:8.2.2637-22.el9_1.1.tuxcare.els11
`vim-minimal` TuxCare:AlmaLinux:9.2 From an advisory covering 3 CVEs	before 2:8.2.2637-22.el9_1.1.tuxcare.els11	2:8.2.2637-22.el9_1.1.tuxcare.els11
`vim` Debian:12	before 2:8.2.3995-1	2:8.2.3995-1
`vim` Debian:13	before 2:8.2.3995-1	2:8.2.3995-1
`vim` Debian:14	before 2:8.2.3995-1	2:8.2.3995-1
`vim` Debian:11 From an advisory covering 32 CVEs	before 2:8.2.2434-3+deb11u2, plus listed versions 2:8.2.2434-32:8.2.2434-3+deb11u1	2:8.2.2434-3+deb11u2
`vim` Mageia:8 From an advisory covering 4 CVEs	before 8.2.4006-1.mga8	8.2.4006-1.mga8

History

History
Recorded	Changed	Sources
Nov 6, 2026	affected	OSV
Nov 4, 2026	facts	OSV
Nov 3, 2026	affected	OSV
Nov 3, 2026	affected
Nov 3, 2026	aliases	EUVD, NVD
Nov 2, 2026	first indexed	CVE List, GitHub Advisories, NVD, OSV

Dates are when Every CVE recorded each change. Upstream dates may differ.

In short

CVE-2021-4173 is a medium vulnerability (CVSS 6.8) in Vim, published December 27, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 1.76%, the 78th percentile. Fixed in vim 8.2.4173-r0.

References

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