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CVE-2020-28873· NVD / CVE Program· CNA mitre

Fluxbb 1.5.11 is affected by a denial of service (DoS) vulnerability by sending an extremely long password via the user login form.

Noroxi assessment

Priority: Monitor (action score 30/100)

  • 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: 0.85% (FIRST EPSS); higher than 58% of all records.
  • Anyone who can reach it over the internet 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

Fluxbb 1.5.11 is affected by a denial of service (DoS) vulnerability by sending an extremely long password via the user login form. When a long password is sent, the password hashing process will result in CPU and memory exhaustion on the server.

HighCVSS 7.5 · v3.1—No exploit No fix recorded
Published
Mar 17, 2021
Updated
Jul 9, 2026
EPSS
0.8% · 58th percentile

Report tools

JSON

Action score

30

Monitor

Low priority for now.

CVSS
30 / 40 · 7.5 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.8%

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-2020-28873

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
fluxbbfluxbb

Affected versions

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

  • fluxbb fluxbb1.5.11

Same product

fluxbb: all records

Other highest-scoring records for the same primary product.

  • CVE-2011-3621A reverse proxy issue exists in FluxBB before 1.4.7 when FORUM_BEHIND_REVERSE_PROXY is enabled.
    39Monitor
  • CVE-2014-9574Directory traversal vulnerability in install.php in FluxBB before 1.5.8 allows remote attackers to include and execute arbitrary local insta
    38Monitor
  • CVE-2014-10029SQL injection vulnerability in profile.php in FluxBB before 1.4.13 and 1.5.x before 1.5.7 allows remote attackers to execute arbitrary SQL c
    31Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2014-10030Jan 13, 2015 · Open redirect vulnerability in forums/login.php in FluxBB before 1.4.13 and 1.5.x before 1.5.7 allows remote attackers to redirect users to
    23Monitor
  • ← EarlierCVE-2020-35240Dec 30, 2020 · FluxBB 1.5.11 is affected by cross-site scripting (XSS in the Blog Content component.
    19Monitor
  • Later →CVE-2021-43677Jan 4, 2022 · Fluxbb v1.4.12 is affected by a Cross Site Scripting (XSS) vulnerability.
    24Monitor

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.

EPSS, last 120 days

FIRST EPSS daily score; only changes of 0.01 or more are recorded (step chart).

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

  • Anyone who can reach it over the internet 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
none
Integrity
none
Availability
high · the service can be disrupted
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
Unchanged
Confidentiality impact
None
Integrity impact
None
Availability impact
High

Weakness class (CWE)

CWE-916 · Use of Password Hash With Insufficient Computational Effort

CVSS vector

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

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.

Change log

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

References

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

All records