Cyber Resilience

CVE-2021-4464

CriticalPublic PoC

Published: 12 November 2025

Published
12 November 2025
Modified
15 April 2026
KEV Added
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Patch
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CVSS Score v4 9.3 CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/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 Score 0.0076 73.7th percentile
Risk Priority 19 60% EPSS · 20% KEV · 20% CVSS

Summary

CVE-2021-4464 is a critical-severity Stack-based Buffer Overflow (CWE-121) vulnerability in Github (inferred from references). Its CVSS base score is 9.3 (Critical).

Operationally, ranked in the top 26.3% 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

FiberHome AN5506-04-FA firmware versions up to and including RP2631 and HG6245D prior to RP2602 contain a stack-based buffer overflow, as the HTTP service ('webs') fails to enforce maximum lengths for Cookie header values. When a cookie longer than 511 bytes…

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is processed, a stack buffer is overrun, leading to a crash or potential control of execution flow.

CWE(s)
CWE-121

Related Threats

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

Affected Assets

Github
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inferred from references and description; NVD did not file a CPE for this CVE

Mitigating Controls

No mitigating controls mapped yet. The per-CVE control annotator has not reached this CVE.

References