← Vulnerability feed

Vulnerability record · CVE-2021-4464 · published 12 November 2025

CVE-2021-4464: Stack-based buffer overflow vulnerability

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.

9.3 CVSS 4.0 Critical EPSS 2.0% · top 19.7% CWE-121 · Stack-based buffer overflow Deferred
9.3CVSS 4.0 base score
2.0%EPSS exploitation probability, 30 days
NoNot in CISA KEV
0Affected product versions listed by NVD
3References
17 Jun 2026Last modified by NVD

Description

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: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:

References

LinkTags
https://pierrekim.github.io/advisories/2021-fiberhome-0x00-ont.txt
https://pierrekim.github.io/blog/2021-01-12-fiberhome-ont-0day-vulnerabilities.html#misc-remote-stack-overflow-an5506
https://www.vulncheck.com/advisories/fiberhome-routers-remote-stack-overflow

Track CVE-2021-4464 inside VULONE

Watch it alongside the ransomware crews, C2 infrastructure and forum chatter that reference it, query it through the API and pull it into your SIEM over TAXII.

Start free Open in platform

Related vulnerabilities

Same products first, then exploited flaws of the same weakness class.

8.8CVE-2026-7273Zyxel gs1900-8 firmware stack-based buffer overflow vulnerabilityA stack-based buffer overflow vulnerability in the CGI program of Zyxel GS1900-48HPv2 firmware versions through 2.90(ABTQ.1)C0 could allow a LAN-base…KEVEPSS 2.5%8.1CVE-2021-27137DD-WRT UPnP M-SEARCH stack buffer overflowDD-WRT before 45724 contains an unsafe strcpy in the UPnP SSDP handling code (ssdp_msearch), reachable via an M-SEARCH request, that overflows a fixe…KEVEPSS 4.0%analysed9.3CVE-2025-53521F5 BIG-IP APM stack buffer overflow allows remote code executionA stack-based buffer overflow (CWE-121) exists in F5 BIG-IP Access Policy Manager when an APM access policy is configured on a virtual server. Specif…KEVEPSS 2.3%analysed8.8CVE-2008-0015Microsoft DirectShow Video ActiveX Control Stack Buffer OverflowA stack-based buffer overflow in the CComVariant::ReadFromStream function in the Active Template Library (ATL) is reachable through the MPEG2TuneRequ…KEVEPSS 77%analysed7.7CVE-2025-20352Cisco IOS and IOS XE SNMP stack overflow allows DoS and root code executionA stack-based buffer overflow in the SNMP subsystem of Cisco IOS and IOS XE Software can be triggered by a crafted SNMP packet sent over IPv4 or IPv6…KEVEPSS 39%analysed9.8CVE-2025-32756Fortinet FortiMail, FortiNDR, FortiVoice, FortiRecorder, FortiCamera stack buffer overflowA stack-based buffer overflow (CWE-121/CWE-787) in multiple Fortinet products is reachable by sending HTTP requests with a specially crafted hash coo…KEVEPSS 30%analysed9.8CVE-2025-42599Qualitia Active! mail stack buffer overflow allows remote code executionActive! mail 6 (BuildInfo 6.60.05008561 and earlier) contains a stack-based buffer overflow (CWE-121). A remote unauthenticated attacker can trigger …KEVEPSS 3.3%analysed9.8CVE-2025-22457Ivanti Connect Secure, Policy Secure and ZTA Gateways stack buffer overflow RCEA stack-based buffer overflow (CWE-121/CWE-787) in Ivanti Connect Secure, Policy Secure and ZTA Gateways allows a remote, unauthenticated attacker to…KEVEPSS 100%analysed

Source: NIST National Vulnerability Database (record CVE-2021-4464), CISA KEV, FIRST EPSS (scores of 2026-09-27). This page is refreshed as NVD updates the record.