CVE-2026-7424: Integer underflow in the DHCPv6 sub-option parser in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adja

Routine

HIGH 8.1WATCHLISTUPGRADE

CVE-2026-7424 is a high-severity flaw (CVSS 8.1) affecting freertos-plus-tcp. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

Integer underflow in the DHCPv6 sub-option parser in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network actor to corrupt the device's IPv6 address assignment, DNS configuration, and lease times, and to cause a denial of service (permanent IP task freeze requiring hardware reset) by sending a single crafted DHCPv6 packet. The issue is present whenever DHCPv6 is enabled. To mitigate this issue, users should upgrad

Why this priority

High severity
On your watchlist

A fixed release or distro patch exists.

Risk facts

CVSS score	8.1 (High)
Attack vector	Adjacent network
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.2% (top 87%)
CISA exploited list	No
Weakness	CWE-191
Published	2026-04-29
Last modified	2026-10-26

Publisher (CNA): AMZN · Vendor: amazon

Last updated 2026-10-26 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2026-04-29 19:16 UTCPublished CVE record published
2026-10-26 20:10 UTCUpdated Record last modified

amazon freertos-plus-tcp UPGRADE

Affected: >= 4.0.0 and < 4.2.6 · >= 4.3.0 and < 4.4.1

Fixed in: 4.2.6, 4.4.1

Safe to downgrade to: a release before 4.0.0

1. Check installed version

apt-cache policy freertos-plus-tcp || rpm -q freertos-plus-tcp || freertos-plus-tcp --version

2. UPGRADE to 4.2.6 (Debian / Ubuntu)

sudo apt update && sudo apt install --only-upgrade freertos-plus-tcp

2. UPGRADE (RHEL / Amazon Linux / Fedora)

sudo dnf upgrade freertos-plus-tcp

Note

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

3. If no update is available yet, DOWNGRADE to a release before 4.0.0 (Debian / Ubuntu)

apt-cache madison freertos-plus-tcp sudo apt install freertos-plus-tcp=<VERSION_BEFORE_4.0.0> sudo apt-mark hold freertos-plus-tcp

3. If no update is available yet, DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list freertos-plus-tcp sudo dnf downgrade freertos-plus-tcp-<VERSION_BEFORE_4.0.0> sudo dnf versionlock add freertos-plus-tcp

Downgrade risk

Downgrading can break dependent software and may reopen older bugs. Read the distro advisory first and test on a non-production host.

After downgrade

Restart the service, and keep the package held until a fixed release ships.

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-2026-7424?

freertos-plus-tcp: upgrade to 4.2.6, 4.4.1. Exact commands for each OS are on this page.

Is CVE-2026-7424 being exploited?

CVE-2026-7424 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-2026-7424 affect?

CVE-2026-7424 affects freertos-plus-tcp. Severity is high (CVSS 8.1). Integer underflow in the DHCPv6 sub-option parser in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network actor to corrupt the device's IPv6 address assignment, DNS configuration, and lease times, and to cause a denial of s

How urgent is CVE-2026-7424?

Priority 37/100. High severity; On your watchlist

Related CVEs

CVE-2026-7426 HIGH 8.1 UPGRADE Insufficient validation of the prefix length field in IPv6 Router Advertisement processing in FreeRTOS-Plus-TC
CVE-2026-7425 MEDIUM 6.5 UPGRADE Insufficient option length validation in the IPv6 Router Advertisement parser in FreeRTOS-Plus-TCP before V4.2
CVE-2026-7422 MEDIUM 6.5 UPGRADE Insufficient packet validation in FreeRTOS-Plus-TCP before V4.2.6 and V4.4.1 allows an adjacent network actor
CVE-2026-7423 MEDIUM 5.3 UPGRADE Integer underflow in the ICMP and ICMPv6 echo reply handlers in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 all

References

← Back to latest CVEs