CVE-2023-29421

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in...

8.8 HighFix available

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Attack profile

How easy it is to exploit

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

What an attacker can affect

Confidentiality: High
Integrity: High
Availability: High

Exploit likelihood

0.92%Up 0.9 points since Apr 6, 2023

What each source reports

NVD Score used 8.8

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Record: CVE-2023-29421
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

CVE List 8.8

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Record: CVE-2023-29421
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

EUVDEUVD-2023-32990 8.8

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Record: EUVD-2023-32990
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-03

GitHub AdvisoriesGHSA-jxf3-h258-gvf9 8.8

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in...

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Record: GHSA-jxf3-h258-gvf9
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Weakness: CWE-787
Updated: 2026-11-02

OSV 8.8

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Record: CVE-2023-29421
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVDEBIAN-CVE-2023-29421 8.8

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Record: DEBIAN-CVE-2023-29421
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

OSVUBUNTU-CVE-2023-29421 8.8

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is an out-of-bounds write in bz3_decode_block.

Record: UBUNTU-CVE-2023-29421
CVSS 3.1: 8.8 HighCVSS:3.1/AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H
Updated: 2026-11-02

Affected products

bzip3 project bzip3

Affected packages

Affected packages
Package	Affected	Fixed
`bzip3` Debian:12	before 1.2.2-2	1.2.2-2
`bzip3` Debian:13	before 1.2.2-2	1.2.2-2
`bzip3` Debian:14	before 1.2.2-2	1.2.2-2
`bzip3` Ubuntu:24.04:LTS	All versions, plus listed versions 1.3.1-11.3.2-11.4.0-1	None known

History

History
Recorded	Changed	Sources
Nov 3, 2026	aliases	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-2023-29421 is a high vulnerability (CVSS 8.8) in Bzip3 Project Bzip3, published April 6, 2023. No source lists public exploit code. EPSS puts the chance of exploitation in the next 30 days at 0.92%, the 60th percentile. Fixed in bzip3 1.2.2-2.

References

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