CVE-2025-50402: FAST FAC1200R F400_FAC1200R_Q is vulnerable to Buffer Overflow in the function sub_80435780 via the parameter

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CRITICAL 9.8REMOTEMITIGATE

CVE-2025-50402 is a critical-severity flaw (CVSS 9.8) affecting fac1200r firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.

FAST FAC1200R F400_FAC1200R_Q is vulnerable to Buffer Overflow in the function sub_80435780 via the parameter string fac_password.

Why this priority

Critical severity
Public exploit reference
Remotely exploitable, no login, no user action

No fix is published yet: follow the downgrade or mitigation steps.

Risk facts

CVSS score	9.8 (Critical)
Attack vector	Network (remote)
Attack complexity	Low
Privileges needed	None
User interaction	None
EPSS exploit chance	0.5% (top 61%)
CISA exploited list	No
Weakness	CWE-120
Published	2025-11-26
Last modified	2026-06-17

Publisher (CNA): MITRE · Vendor: fastcom

Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score

Am I affected?

Timeline

2025-11-26 16:15 UTCPublished CVE record published
2026-06-17 09:35 UTCUpdated Record last modified

fastcom fac1200r firmware MITIGATE

Affected: f400_fac1200r_q

Fixed in: no fixed release known

Safe to downgrade to: a release before f400_fac1200r_q

Check your OS release

cat /etc/os-release; uname -r

Debian / Ubuntu

sudo apt update && sudo apt full-upgrade

RHEL / Amazon Linux / Fedora

sudo dnf upgrade --refresh

Windows

Install the latest cumulative update from Windows Update

If no patch exists yet

OS downgrades are not safe. Apply the vendor mitigation from the advisory and restrict exposure.

Verify at the official source NVD · CVE Program · Report a problem with this page
Scores and fixes here are computed automatically from those and other public sources. Confirm with the vendor advisory before changing production systems.

Quick answers

How do I fix CVE-2025-50402?

fac1200r firmware: mitigate or apply the listed mitigation. Exact commands for each OS are on this page.

Is CVE-2025-50402 being exploited?

CVE-2025-50402 is not on the CISA Known Exploited Vulnerabilities list at the time of the last update. Check again, as this can change.

What does CVE-2025-50402 affect?

CVE-2025-50402 affects fac1200r firmware. Severity is critical (CVSS 9.8). FAST FAC1200R F400_FAC1200R_Q is vulnerable to Buffer Overflow in the function sub_80435780 via the parameter string fac_password.

How urgent is CVE-2025-50402?

Priority 54/100. Critical severity; Public exploit reference; Remotely exploitable, no login, no user action

Related CVEs

CVE-2025-50399 CRITICAL 9.8 MITIGATE FAST FAC1200R F400_FAC1200R_Q is vulnerable to Buffer Overflow in the function sub_80435780 via the parameter

References

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