Cyber Resilience

CVE-2021-42697

HighPublic PoCDDoS

Published: 02 November 2021

Published
02 November 2021
Modified
21 November 2024
KEV Added
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Patch
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CVSS Score v3.1 7.5 CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H
EPSS Score 0.7554 98.9th percentile
Risk Priority 60 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-42697 is a high-severity Uncontrolled Recursion (CWE-674) vulnerability in Akka Http Server. Its CVSS base score is 7.5 (High).

Operationally, ranked in the top 1.1% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.

EU & UK References

Vulnerability details

Akka HTTP 10.1.x before 10.1.15 and 10.2.x before 10.2.7 can encounter stack exhaustion while parsing HTTP headers, which allows a remote attacker to conduct a Denial of Service attack by sending a User-Agent header with deeply nested comments.

CWE(s)
CWE-674

Related Threats

No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.

Affected Assets

akka
http server
10.1.0 — 10.1.15 · 10.2.0 — 10.2.7

Mitigating Controls

Likely Mitigating Controls AI

Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.

CP-7 Alternate Processing Site
addresses: CWE-674

Supports resumption at alternate site when uncontrolled recursion causes primary site failure or crash.

SC-5 Denial-of-service Protection
addresses: CWE-674

Prevents uncontrolled recursion that exhausts stack or CPU resources.

References