CVE-2021-4464

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

CVSS v4.0

9.3 CRITICALCVSS: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

2.03% chance of exploitation in the next 30 days, 80th percentile

Published

2025-11-12

Updated

2025-11-21

Proof-of-concept exploits (2)

• https://pierrekim.github.io/blog/2021-01-12-fiberhome-ont-0day-vulnerabilities.html#misc-…
• https://pierrekim.github.io/advisories/2021-fiberhome-0x00-ont.txt

References

• CVE Record
• NVD entry

Related

• CVE-2021-44632
• CVE-2021-44648
• CVE-2021-44631
• CVE-2021-44649
• CVE-2021-44630
• CVE-2021-4465