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CVE-2026-7423
Integer Underflow in ICMP Echo Reply Processing in FreeRTOS-Plus-TCP
Medium6.0EPSS 0.22%
- Published
- Updated
- Reserved
- Assigned by
- AMZN
Description
Integer underflow in the ICMP and ICMPv6 echo reply handlers in FreeRTOS-Plus-TCP before V4.4.1 and V4.2.6 allows an adjacent network user to cause a denial of service (device crash) when outgoing ping support is enabled, because header sizes are subtracted from a packet length field without validating the field is large enough, resulting in a heap out-of-bounds read of up to approximately 65KB. To mitigate this issue, users should upgrade to the fixed version when available.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| AMZNCNA (assigner) | 4.0 | Medium6.0 | CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| AMZNCNA (assigner) | 3.1 | Medium5.3 | CVSS:3.1/AV:A/AC:H/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Analyzed | 4.0 | Medium6.0 | CVSS:4.0/AV:A/AC:L/AT:P/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X |
- EPSS (exploitation in 30 days)
- 0.22% · top 87% of all CVEs (6 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
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The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.0.
Weakness
Affected products
- affected 4.0.0 – < 4.2.6
- affected 4.3.0 – < 4.4.1
- unaffected 4.2.6
- unaffected 4.4.1
References (4)
- https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.4.1 (opens in a new tab)patch
- https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/releases/tag/V4.2.6 (opens in a new tab)patch
- https://aws.amazon.com/security/security-bulletins/2026-021-aws/ (opens in a new tab)vendor-advisory
- https://github.com/FreeRTOS/FreeRTOS-Plus-TCP/security/advisories/GHSA-7r59-2pgv-9v2r (opens in a new tab)third-party-advisory
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2026-7423)Record last updated .