PatchTheCVECVE-2020-26887: FRITZ!OS before 7.21 on FRITZ!Box devices allows a bypass of a DNS Rebinding protection mechanism.
CVE-2020-26887 is a high-severity flaw (CVSS 7.8) affecting fritz\!box 7490 firmware. Below: why it ranks where it does, which versions are affected, what to do, and the exact commands.
FRITZ!OS before 7.21 on FRITZ!Box devices allows a bypass of a DNS Rebinding protection mechanism.
Why this priority
- High severity
- Public exploit reference
A fixed release or distro patch exists.
Risk facts
| CVSS score | 7.8 (High) |
| Attack vector | Local |
| Attack complexity | Low |
| Privileges needed | Low |
| User interaction | None |
| EPSS exploit chance | 1.4% (top 27%) |
| CISA exploited list | No |
| Published | 2020-10-23 |
| Last modified | 2026-06-17 |
Last updated 2026-06-17 · Sources: CVE Program, NVD, CISA KEV, EPSS and vendor advisories · How we score
Am I affected?
Timeline
- Published CVE record published
- Updated Record last modified
Public exploits and detection
Public code exists for this CVE. Treat unpatched systems as at risk, and only run PoCs in a lab.
- Exploit-DB: FRITZ!Box 7.20 - DNS Rebinding Protection Bypass
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-2020-26887?
fritz\!box 7490 firmware: upgrade to 7.21. Exact commands for each OS are on this page.
Is CVE-2020-26887 being exploited?
CVE-2020-26887 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-2020-26887 affect?
CVE-2020-26887 affects fritz\!box 7490 firmware. Severity is high (CVSS 7.8). FRITZ!OS before 7.21 on FRITZ!Box devices allows a bypass of a DNS Rebinding protection mechanism.
How urgent is CVE-2020-26887?
Priority 50/100. High severity; Public exploit reference