Description
Eclipse Wakaama before snapshot/2026-05-26 contains an unbounded memory allocation vulnerability in the CoAP Block1 handler within coap/block.c that allows unauthenticated remote attackers to exhaust server memory by sending a sequence of Block1 PUT requests with incrementing block numbers. Attackers can target the registration endpoint over UDP without authentication, causing the server to repeatedly reallocate a growing accumulation buffer by appending each block payload without enforcing any maximum total size limit, resulting in denial of service through memory exhaustion.
Severity (CVSS)
| Base score | 8.7 |
|---|---|
| Severity | High |
| Version | CVSS 4.0 |
| Vector | CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N |
| Provided by | CNA |
Weaknesses
- CWE-770 — Allocation of Resources Without Limits or Throttling
Affected products
| Vendor | Product | Versions |
|---|---|---|
| eclipse-wakaama | wakaama | 0 to <snapshot/2026-05-26 |
References
- https://github.com/eclipse-wakaama/wakaama/releases/tag/snapshots%2F2026-05-26 (release-notes)
- https://github.com/eclipse-wakaama/wakaama/pull/881 (issue-tracking)
- https://github.com/eclipse-wakaama/wakaama/commit/a83f1ca28fa090fbc03c3669fef40daf4f89cd03 (patch)
- https://www.vulncheck.com/advisories/eclipse-wakaama-coap-block1-handler-unbounded-memory-allocation-dos (third-party-advisory)
Generated from the official CVE List on 03 Jul 2026 07:05 UTC.