CVE-2020-27338: An issue was discovered in Treck IPv6 before 6.0.1.68

Q: How do I fix CVE-2020-27338?

ipv6: upgrade to 6.0.1.68. Exact commands for each OS are on this page.

Q: Is CVE-2020-27338 being exploited?

CVE-2020-27338 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-2020-27338 affect?

CVE-2020-27338 affects ipv6. Severity is medium (CVSS 5.9). An issue was discovered in Treck IPv6 before 6.0.1.68. Improper Input Validation in the DHCPv6 client component allows an unauthenticated remote attacker to cause an Out of Bounds Read, and possibly a Denial of Service via adjacent network

Q: How urgent is CVE-2020-27338?

Priority 35/100. No elevated risk signals yet.

Routine

MEDIUM 5.9UPGRADE

CVE-2020-27338 is a medium-severity flaw (CVSS 5.9) affecting ipv6. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

An issue was discovered in Treck IPv6 before 6.0.1.68. Improper Input Validation in the DHCPv6 client component allows an unauthenticated remote attacker to cause an Out of Bounds Read, and possibly a Denial of Service via adjacent network access.

Why this priority

No elevated risk signals yet

A fixed release or distro patch exists.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Adjacent network
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-20, CWE-125
Published	2020-12-22
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: treck

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

Am I affected?

Timeline

2020-12-22 22:15 UTCPublished CVE record published
2026-06-17 03:09 UTCUpdated Record last modified

treck ipv6 UPGRADE

Affected: < 6.0.1.68

Fixed in: 6.0.1.68

Safe to downgrade to: no unaffected older release

1. Check installed version

apt-cache policy ipv6 || rpm -q ipv6 || ipv6 --version

2. UPGRADE to 6.0.1.68 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade ipv6

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade ipv6

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-2020-27338?

ipv6: upgrade to 6.0.1.68. Exact commands for each OS are on this page.

Is CVE-2020-27338 being exploited?

CVE-2020-27338 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-2020-27338 affect?

CVE-2020-27338 affects ipv6. Severity is medium (CVSS 5.9). An issue was discovered in Treck IPv6 before 6.0.1.68. Improper Input Validation in the DHCPv6 client component allows an unauthenticated remote attacker to cause an Out of Bounds Read, and possibly a Denial of Service via adjacent network

How urgent is CVE-2020-27338?

Priority 35/100. No elevated risk signals yet.

Related CVEs

CVE-2025-23019 MEDIUM 5.4 MITIGATE IPv6-in-IPv4 tunneling (RFC 4213) allows an attacker to spoof and route traffic via an exposed network interfa
CVE-2025-23018 MEDIUM 5.4 MITIGATE IPv4-in-IPv6 and IPv6-in-IPv6 tunneling (RFC 2473) do not require the validation or verification of the source
CVE-2020-27337 HIGH 7.3 UPGRADE An issue was discovered in Treck IPv6 before 6.0.1.68
CVE-2020-27336 LOW 3.7 UPGRADE An issue was discovered in Treck IPv6 before 6.0.1.68
CVE-2016-10142 HIGH 8.6 MITIGATE An issue was discovered in the IPv6 protocol specification, related to ICMP Packet Too Big (PTB) messages

References

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