CVE-2026-7423Integer Underflow in ICMP Echo Reply Processing in FreeRTOS-Plus-TCP
- 6.0MediumCVSS base score
- 0.22%Exploitation in 30 daysEPSS · top 87% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
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.
Timeline
ID reserved
By AMZN
Published
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
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 (15 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: no · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: Medium 6.0.
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
References4
- 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)
- EUVD EUVD-2026-26276 (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://cveledger.app/cve/CVE-2026-7423)Record last updated .