CVE-2023-29420: An issue was discovered in libbzip3.a in bzip3 before 1.2.3

Q: How do I fix CVE-2023-29420?

bzip3: upgrade to 1.2.3. Exact commands for each OS are on this page.

Q: Is CVE-2023-29420 being exploited?

CVE-2023-29420 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

Q: What does CVE-2023-29420 affect?

CVE-2023-29420 affects bzip3. Severity is medium (CVSS 6.5). An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is a crash caused by an invalid memmove in bz3_decode_block.

Q: How urgent is CVE-2023-29420?

Priority 43/100. Public exploit reference

This month

MEDIUM 6.5UPGRADE

CVE-2023-29420 is a medium-severity flaw (CVSS 6.5) affecting bzip3. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is a crash caused by an invalid memmove in bz3_decode_block.

Why this priority

Public exploit reference

A fixed release or distro patch exists.

Risk facts

CVSS score	6.5 (Medium)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	Required
EPSS exploit chance	0.9% (top 41%)
CISA exploited list	No
Weakness	CWE-119
Published	2023-04-06
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: bzip3 project

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2023-04-06 05:15 UTCPublished CVE record published
2026-06-17 05:50 UTCUpdated Record last modified

bzip3 project bzip3 UPGRADE

Affected: < 1.2.3

Fixed in: 1.2.3

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy bzip3 || rpm -q bzip3 || bzip3 --version

2. UPGRADE to 1.2.3 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade bzip3

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade bzip3

Note

Distros often backport fixes without changing the version number. Confirm with the distro advisory or changelog.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2023-29420?

bzip3: upgrade to 1.2.3. Exact commands for each OS are on this page.

Is CVE-2023-29420 being exploited?

CVE-2023-29420 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2023-29420 affect?

CVE-2023-29420 affects bzip3. Severity is medium (CVSS 6.5). An issue was discovered in libbzip3.a in bzip3 before 1.2.3. There is a crash caused by an invalid memmove in bz3_decode_block.

How urgent is CVE-2023-29420?

Priority 43/100. Public exploit reference

Related CVEs

CVE-2023-29421 HIGH 8.8 UPGRADE An issue was discovered in libbzip3.a in bzip3 before 1.2.3
CVE-2023-29419 MEDIUM 6.5 UPGRADE An issue was discovered in libbzip3.a in bzip3 before 1.2.3
CVE-2023-29418 MEDIUM 6.5 UPGRADE An issue was discovered in libbzip3.a in bzip3 before 1.2.3
CVE-2023-29417 MEDIUM 6.5 DOWNGRADE An issue was discovered in libbzip3.a in bzip3 1.2.2
CVE-2023-29416 MEDIUM 6.5 UPGRADE An issue was discovered in libbzip3.a in bzip3 before 1.3.0

References

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