CVE-2023-39540: A denial of service vulnerability exists in the ICMP and ICMPv6 parsing functionality of Weston Embedded uC-TC

This week

MEDIUM 5.9REMOTEDOWNGRADE

CVE-2023-39540 is a medium-severity flaw (CVSS 5.9) affecting uc-tcp-ip. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

A denial of service vulnerability exists in the ICMP and ICMPv6 parsing functionality of Weston Embedded uC-TCP-IP v3.06.01. A specially crafted network packet can lead to an out-of-bounds read. An attacker can send a malicious packet to trigger this vulnerability.This vulnerability concerns a denial of service within the parsing an IPv4 ICMP packet.

Why this priority

Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	5.9 (Medium)
Attack vector	Network (remote)
Attack complexity	High
Privileges needed	None
User interaction	None
EPSS exploit chance	0.8% (top 43%)
CISA exploited list	No
Weakness	CWE-126, CWE-125
Published	2024-02-20
Last modified	2026-06-17

Publisher (CNA): Talos · Vendor: weston-embedded

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

Am I affected?

Timeline

2024-02-20 15:15 UTCPublished CVE record published
2026-06-17 06:12 UTCUpdated Record last modified

weston-embedded uc-tcp-ip DOWNGRADE

Affected: 3.06.01

Fixed in: no fixed release known

Safe to downgrade to: a release before 3.06.01

1. Check installed version

apt-cache policy uc-tcp-ip || rpm -q uc-tcp-ip || uc-tcp-ip --version

2. No fixed release: DOWNGRADE to a release before 3.06.01 (Debian / Ubuntu)

apt-cache madison uc-tcp-ip sudo apt install uc-tcp-ip=<VERSION_BEFORE_3.06.01> sudo apt-mark hold uc-tcp-ip

2. No fixed release: DOWNGRADE (RHEL / Amazon Linux / Fedora)

dnf --showduplicates list uc-tcp-ip sudo dnf downgrade uc-tcp-ip-<VERSION_BEFORE_3.06.01> sudo dnf versionlock add uc-tcp-ip

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-2023-39540?

uc-tcp-ip: downgrade or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2023-39540 being exploited?

CVE-2023-39540 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-2023-39540 affect?

CVE-2023-39540 affects uc-tcp-ip. Severity is medium (CVSS 5.9). A denial of service vulnerability exists in the ICMP and ICMPv6 parsing functionality of Weston Embedded uC-TCP-IP v3.06.01. A specially crafted network packet can lead to an out-of-bounds read. An attacker can send a malicious packet to tr

How urgent is CVE-2023-39540?

Priority 45/100. Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2023-39541 MEDIUM 5.9 DOWNGRADE A denial of service vulnerability exists in the ICMP and ICMPv6 parsing functionality of Weston Embedded uC-TC
CVE-2023-38562 HIGH 8.7 DOWNGRADE A double-free vulnerability exists in the IP header loopback parsing functionality of Weston Embedded uC-TCP-I

References

← Back to latest CVEs