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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.

PUBLISHED Reserved 2026-06-30 | Published 2026-07-02 | Updated 2026-07-14 | Assigner VulnCheck




HIGH: 8.7CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N

HIGH: 7.5CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Problem types

Allocation of Resources Without Limits or Throttling

Product status

Default status
affected

Any version before snapshot/2026-05-26
affected

Credits

Kazuma Matsumoto, a security researcher at GMO Cybersecurity by IERAE, Inc. finder

VulnCheck finder

References

github.com/...aama/wakaama/releases/tag/snapshots/2026-05-26 (Release Notes) release-notes

github.com/eclipse-wakaama/wakaama/pull/881 (Fix PR) issue-tracking

github.com/...ommit/a83f1ca28fa090fbc03c3669fef40daf4f89cd03 (Fix Patch) patch

www.vulncheck.com/...handler-unbounded-memory-allocation-dos third-party-advisory

cve.org (CVE-2026-58465)

nvd.nist.gov (CVE-2026-58465)

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