CVE-2021-31819: In Halibut versions prior to 4.4.7 there is a deserialisation vulnerability that could allow remote code execu

Q: How do I fix CVE-2021-31819?

halibut: upgrade to 4.4.7. Exact commands for each OS are on this page.

Q: Is CVE-2021-31819 being exploited?

CVE-2021-31819 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-2021-31819 affect?

CVE-2021-31819 affects halibut. Severity is critical (CVSS 9.8). In Halibut versions prior to 4.4.7 there is a deserialisation vulnerability that could allow remote code execution on systems that already trust each other based on certificate verification.

Q: How urgent is CVE-2021-31819?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

This week

CRITICAL 9.8REMOTEUPGRADE

CVE-2021-31819 is a critical-severity flaw (CVSS 9.8) affecting halibut. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

In Halibut versions prior to 4.4.7 there is a deserialisation vulnerability that could allow remote code execution on systems that already trust each other based on certificate verification.

Why this priority

Critical severity
Remotely exploitable, no login, no user action

A fixed release or distro patch exists.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	2.4% (top 16%)
CISA exploited list	No
Weakness	CWE-502
Published	2021-09-22
Last modified	2026-06-17

Publisher (CNA): Octopus Deploy · Vendor: octopus

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

Am I affected?

Timeline

2021-09-22 02:15 UTCPublished CVE record published
2026-06-17 03:52 UTCUpdated Record last modified

octopus halibut UPGRADE

Affected: < 4.4.7

Fixed in: 4.4.7

Safe to downgrade to: no unaffected older release

1. Check installed version

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

2. UPGRADE to 4.4.7 (Debian / Ubuntu)

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

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade halibut

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-2021-31819?

halibut: upgrade to 4.4.7. Exact commands for each OS are on this page.

Is CVE-2021-31819 being exploited?

CVE-2021-31819 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-2021-31819 affect?

CVE-2021-31819 affects halibut. Severity is critical (CVSS 9.8). In Halibut versions prior to 4.4.7 there is a deserialisation vulnerability that could allow remote code execution on systems that already trust each other based on certificate verification.

How urgent is CVE-2021-31819?

Priority 60/100. Critical severity; Remotely exploitable, no login, no user action

Related CVEs

CVE-2021-42614 HIGH 7.8 DOWNGRADE MITIGATE A use after free in info_width_internal in bk_info.c in Halibut 1.2 allows an attacker to cause a segmentation
CVE-2021-42613 HIGH 7.8 DOWNGRADE MITIGATE A double free in cleanup_index in index.c in Halibut 1.2 allows an attacker to cause a denial of service or po
CVE-2021-42612 HIGH 7.8 DOWNGRADE MITIGATE A use after free in cleanup_index in index.c in Halibut 1.2 allows an attacker to cause a segmentation fault o

References

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