CVE-2021-23422

Arbitrary Code Injection

7.8 HighFix available

This affects the package bikeshed before 3.0.0. This can occur when an untrusted source file containing Inline Tag Command metadata is processed. When an arbitrary OS command is executed, the command output would be included in the HTML output.

Attack profile

How easy it is to exploit

Attack vector: Local
Complexity: Low
Privileges needed: None
User interaction: Required

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.79%Up 0.2 points since Aug 16, 2021

What each source reports

CVE List Score used 7.8

Arbitrary Code Injection

Record: CVE-2021-23422
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

EUVDEUVD-2021-0033 7.8

Record: EUVD-2021-0033
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

GitHub AdvisoriesGHSA-87cj-px37-rc3x 7.8

OS Command Injection in bikeshed

Record: GHSA-87cj-px37-rc3x
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-78
Updated: 2026-11-02

NVD 7.8

Record: CVE-2021-23422
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 2.0: 6.8 MediumAV:N/AC:M/Au:N/C:P/I:P/A:P
Weakness: CWE-78
Updated: 2026-11-02

OSV 7.8

Record: CVE-2021-23422
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

OSVGHSA-87cj-px37-rc3x 7.8

OS Command Injection in bikeshed

Record: GHSA-87cj-px37-rc3x
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-78
Updated: 2026-11-02

OSVUBUNTU-CVE-2021-23422 7.8

Record: UBUNTU-CVE-2021-23422
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

OSVPYSEC-2021-116 No score

Record: PYSEC-2021-116
Updated: 2026-11-02

Affected products

bikeshed project bikeshed

Affected packages

Affected packages
Package	Affected	Fixed
`bikeshed` PyPI	before 3.0.0	3.0.0
`bikeshed` PyPI	before 3.0.0, plus listed versions 1.0.01.0.11.0.101.0.21.0.3 Show 41 moreShow less 1.0.41.0.51.0.61.0.71.0.81.0.91.1.01.2.01.2.11.2.21.3.01.4.01.4.11.4.21.4.31.4.41.5.01.5.11.5.21.5.31.6.01.6.11.6.21.6.31.7.02.0.02.1.02.2.02.2.12.2.22.2.32.3.02.3.12.4.02.4.12.4.22.4.32.4.42.4.52.4.62.4.7	3.0.0
`bikeshed` Ubuntu:16.04:LTS	All versions, plus listed versions 1.53-0ubuntu11.60-0ubuntu11.61-0ubuntu11.62-0ubuntu11.65-0ubuntu1	None known
`bikeshed` Ubuntu:18.04:LTS	All versions, plus listed versions 1.71-0ubuntu11.72-0ubuntu11.73-0ubuntu1	None known
`bikeshed` Ubuntu:20.04:LTS	All versions, plus listed versions 1.78-0ubuntu1	None known
`bikeshed` Ubuntu:22.04:LTS	All versions, plus listed versions 1.78-0ubuntu1	None known
`bikeshed` Ubuntu:24.04:LTS	All versions, plus listed versions 1.78-0ubuntu1	None known
`bikeshed` Ubuntu:25.10	All versions, plus listed versions 1.78-0ubuntu1	None known
`bikeshed` Ubuntu:26.10	All versions, plus listed versions 1.78-0ubuntu2	None known
`bikeshed` Ubuntu:26.04:LTS	All versions, plus listed versions 1.78-0ubuntu11.78-0ubuntu2	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases, published	EUVD
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-2021-23422 is a high vulnerability (CVSS 7.8) in Bikeshed Project Bikeshed, published August 16, 2021. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.79%, the 56th percentile. Fixed in bikeshed 3.0.0.