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NVD / CVE Program· CNA jpcert

CVE-2021-3511: Disclosure of sensitive information to an unauthorized user vulnerability in Buffalo broadband routers (BHR-4GRV firmware Ver.1.99 and prior

Noroxi assessment

Priority: Monitor (action score 17/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.51% (FIRST EPSS).
  • Someone on the same network segment can trigger it. No account or password is required. No user action is required. No special conditions are required; it is repeatable.
  • According to the record, no fixed version is available yet.

Low priority for now. Update when a fix is released; follow the vendor's advisory.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

Disclosure of sensitive information to an unauthorized user vulnerability in Buffalo broadband routers (BHR-4GRV firmware Ver.1.99 and prior, DWR-HP-G300NH firmware Ver.1.83 and prior, HW-450HP-ZWE firmware Ver.1.99 and prior, WHR-300HP firmware Ver.1.99 and prior, WHR-300 firmware Ver.1.99 and prior, WHR-G301N firmware Ver.1.86 and prior, WHR-HP-G300N firmware Ver.1.99 and prior, WHR-HP-GN firmware Ver.1.86 and prior, WPL-05G300 firmware Ver.1.87 and prior, WZR-450HP-CWT firmware Ver.1.99 and prior, WZR-450HP-UB firmware Ver.1.99 and prior, WZR-HP-AG300H firmware Ver.1.75 and prior, WZR-HP-G300NH firmware Ver.1.83 and prior, WZR-HP-G301NH firmware Ver.1.83 and prior, WZR-HP-G302H firmware Ver.1.85 and prior, WZR-HP-G450H firmware Ver.1.89 and prior, WZR-300HP firmware Ver.1.99 and prior, WZR-450HP firmware Ver.1.99 and prior, WZR-600DHP firmware Ver.1.99 and prior, WZR-D1100H firmware Ver.1.99 and prior, FS-HP-G300N firmware Ver.3.32 and prior, FS-600DHP firmware Ver.3.38 and prior, FS-R600DHP firmware Ver.3.39 and prior, and FS-G300N firmware Ver.3.13 and prior) allows remote unauthenticated attackers to obtain information such as configuration via unspecified vectors.

MediumCVSS 4.3 · v3.1—No exploit No fix recorded
Published
Apr 27, 2021
Updated
Jun 17, 2026
EPSS
0.5% · 43th percentile
CWE
—

Report tools

JSON

Action score

17

Monitor

Low priority for now.

CVSS
17 / 40 · 4.3 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.5%

Get told when this record changes

  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • No fixed version yet

If any of these changes, we'll tell you in the daily email digest.

Follow CVE-2021-3511

When you'll hear from us

  • when it enters CISA KEV
  • when exploit code appears or is weaponized
  • when the record is updated (including a fixed version)
  • when EPSS rises 20 points in a week

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Noroxi analysis

What does it mean in your environment?

The assessment above is generated automatically from the record's data; it doesn't know your environment. Our team verifies on your systems whether this vulnerability is actually exploitable and which mitigation is enough.

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Affected systems

Is your version affected?

Pick the product and type the version you run. It's compared with this record's version ranges in your browser; the version isn't sent anywhere.

VendorProduct
buffalobhr-4grv firmware
buffalobhr-4grv
buffalodwr-hp-g300nh firmware
buffalodwr-hp-g300nh
buffalohw-450hp-zwe firmware
buffalohw-450hp-zwe
buffalowhr-300hp firmware
buffalowhr-300hp
buffalowhr-300 firmware
buffalowhr-300
buffalowhr-g301n firmware
buffalowhr-g301n

and 36 more

Affected versions

NVD version ranges (for catalog products). Add the product to your stack with a version and matching uses these.

  • buffalo bhr-4grv firmwarebefore 2.00
  • buffalo dwr-hp-g300nh firmwarebefore 1.84
  • buffalo fs-600dhp firmwarebefore 3.40
  • buffalo fs-g300n firmwarebefore 3.14
  • buffalo fs-hp-g300n firmwarebefore 3.33
  • buffalo fs-r600dhp firmwarebefore 3.40
  • buffalo hw-450hp-zwe firmwarebefore 2.00
  • buffalo whr-300 firmwarebefore 2.00
  • buffalo whr-300hp firmwarebefore 2.00
  • buffalo whr-g301n firmwarebefore 1.87
  • buffalo whr-hp-g300n firmwarebefore 2.00
  • buffalo whr-hp-gn firmwarebefore 1.87
  • buffalo wpl-05g300 firmwarebefore 1.88
  • buffalo wzr-300hp firmwarebefore 2.00
  • buffalo wzr-450hp firmwarebefore 2.00
  • buffalo wzr-450hp-cwt firmwarebefore 2.00
  • buffalo wzr-450hp-ub firmwarebefore 2.00
  • buffalo wzr-600dhp firmwarebefore 2.00
  • buffalo wzr-d1100h firmwarebefore 2.00
  • buffalo wzr-hp-ag300h firmwarebefore 1.76

Versions reported by the vendor

Affected version ranges reported by the assigning authority (jpcert). Independent of NVD's CPE analysis and usually ahead of it.

  • BUFFALO INC. Buffalo broadband routers

    • BHR-4GRV firmware Ver.1.99 and prior, DWR-HP-G300NH firmware Ver.1.83 and prior, HW-450HP-ZWE firmware Ver.1.99 and prior, WHR-300HP firmware Ver.1.99 and prior, WHR-300 firmware Ver.1.99 and prior, Waffected

Same product

buffalo: all records

Other highest-scoring records for the same primary product.

  • CVE-2021-3512Improper access control vulnerability in Buffalo broadband routers (BHR-4GRV firmware Ver.1.99 and prior, DWR-HP-G300NH firmware Ver.1.83 an
    35Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

No fix version is recorded for this entry. Check the references for vendor advisories.

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

Attack conditions

  • Someone on the same network segment can trigger it.
  • No account or password is required.
  • No user action is required.
  • No special conditions are required; it is repeatable.

If successful

Confidentiality
low · data can be read
Integrity
none
Availability
none
Attack vector
Adjacent
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

—

CVSS vector

CVSS:3.1/AV:A/AC:L/PR:N/UI:N/S:U/C:L/I:N/A:N

nvd-primary

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

No changes recorded on tracked fields yet. Score, KEV, exploit maturity and fix status changes appear here.

References

Show all references (1 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

All records