NULL pointer dereference in ICMPv6 Packet Too Big processing when the destination table is full
Affects Eclipse ThreadX NetX Duo 6.4.5.202504 through 6.5.2.202603a built with IPv6 path MTU discovery. Fixed in NetX Duo 6.5.2.202603b.
Written by anthropic/claude-haiku-5.5 from the sources below. Verify against them.
- Exploited
- No known exploitation
- Fix
- Fixed in 6.5.2.202603b
- Who is exposed
- Specific setups only
Do first: Check whether your setup matches what the bug needs. Built with IPv6 path MTU discovery (FEATURE_NX_IPV6 and NX_ENABLE_IPV6_PATH_MTU_DISCOVERY). NetX Duo version from 6.4.5.202504 through 6.5.2.202603a. Destination table is full, so the add fails and returns a NULL entry.
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- Published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- A 0-100 score for how much a CVE matters across the industry: exploitation, exposure, how widely the software is used, severity and whether a fix exists.What do these mean? →
- 24/100 · provisional
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in 6.5.2.202603b
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: yes
- Technical impact: partial
Summary
Eclipse ThreadX NetX Duo, the embedded TCP/IP networking stack, is affected when built with IPv6 path MTU discovery enabled. A remote attacker on the network can crash its IP helper thread, halting all network processing on the device.
Read the original description
In Eclipse ThreadX NetX Duo versions 6.4.5.202504 through 6.5.2.202603a, built with IPv6 path MTU discovery, the ICMPv6 Packet Too Big handler uses the destination-table entry it adds without checking that the add succeeded. A sender on the network can fill the destination table with Packet Too Big messages quoting new destinations, after which the next message makes the IP helper thread dereference a NULL pointer, crashing it on targets that fault on address 0 and stopping all network processing.
What to do
Check whether your setup matches what the bug needs.
Built with IPv6 path MTU discovery (FEATURE_NX_IPV6 and NX_ENABLE_IPV6_PATH_MTU_DISCOVERY). NetX Duo version from 6.4.5.202504 through 6.5.2.202603a. Destination table is full, so the add fails and returns a NULL entry.Upgrade to a fixed version: 6.5.2.202603b.
Workaround: Building without NX_ENABLE_IPV6_PATH_MTU_DISCOVERY removes the vulnerable code.
Timeline
- CVE published
- First seen by cve.now
- CISA SSVC assessment
Exploitation: none · Automatable: yes · Technical impact: partial
- Record last updated
Affected versions
- Eclipse Foundation Eclipse ThreadX
From 6.4.5 · through 6.5.2.202603a
Evidence 2
- Advisory
- Link
Corrections
None so far.
Something wrong on this page? Report an error. Every fix is listed here.
Questions about CVE-2026-114408
What does this mean?
When the IPv6 path MTU destination table is full, the add fails and returns a NULL entry, and the code then dereferences it. Sending Packet Too Big messages that quote new destinations can crash the IP helper thread, which stops all network processing (a denial of service).Source: github.com
Am I affected, and how do I check?
Versions from NetX Duo 6.4.5.202504 through 6.5.2.202603a are affected, but only builds with FEATURE_NX_IPV6 and NX_ENABLE_IPV6_PATH_MTU_DISCOVERY enabled. To check, look at the NetX Duo version in the project and at whether those two build settings are defined in the configuration.Source: github.com
What should I do about it?
Upgrade to NetX Duo 6.5.2.202603b, which fixes the issue. If you cannot upgrade, rebuild without NX_ENABLE_IPV6_PATH_MTU_DISCOVERY, which removes the vulnerable code.Source: github.com
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data