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NVD / CVE Program· CNA mitre

CVE-2018-1000503: MyBB Group MyBB contains a Incorrect Access Control vulnerability in Private forums that can result in Users can view posts from private for

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: 0.62% (FIRST EPSS).
  • Anyone who can reach it over the internet can trigger it. A low-privileged account is enough. No user action is required. No special conditions are required; it is repeatable.
  • Fixed version: n/a n/a 1.8.15.

Low priority for now. Upgrade to n/a n/a 1.8.15 or later.

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

MyBB Group MyBB contains a Incorrect Access Control vulnerability in Private forums that can result in Users can view posts from private forums without having the password. This attack appear to be exploitable via Subscribe to a forum through IDOR. This vulnerability appears to have been fixed in 1.8.15.

MediumCVSS 4.3 · v3.0—No exploit Fix available
Published
Jun 26, 2018
Updated
Jun 16, 2026
EPSS
0.6% · 49th percentile

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 · 0.6%

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  • Not in KEV: no record of exploitation in the wild
  • No public exploit code on record
  • A fix has been released

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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
mybbmybb

Affected versions

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

  • mybb mybbbefore 1.8.15

Same product

mybb: all records

Other highest-scoring records for the same primary product.

  • CVE-2011-10018myBB 1.6.4 Backdoor Arbitrary Command Execution
    60This week
  • CVE-2022-24734Remote code execution in mybb
    51Plan
  • CVE-2018-17128A Persistent XSS issue was discovered in the Visual Editor in MyBB before 1.8.19 via a Video MyCode.
    43Plan

Published before and after this one in the same product

  • ← EarlierCVE-2018-10678May 13, 2018 · MyBB 1.8.15, when accessed with Microsoft Edge, mishandles 'target="_blank" rel="noopener"' in A elements, which makes it easier for remote
    24Monitor
  • ← EarlierCVE-2018-1000502Jun 26, 2018 · MyBB Group MyBB contains a File Inclusion vulnerability in Admin panel (Tools and Maintenance -> Task Manager -> Add New Task) that can resu
    28Monitor
  • Later →CVE-2018-15596Aug 28, 2018 · An issue was discovered in inc/class_feedgeneration.php in MyBB 1.8.17.
    25Monitor

Remediation

Which version to upgrade to

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

Product / packageFixed versionSource
n/a n/a1.8.15 · descriptionVendor (CNA)

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

  • Anyone who can reach it over the internet can trigger it.
  • A low-privileged account is enough.
  • 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
Network
Attack complexity
Low
Privileges required
Low
User interaction
None
Scope
Unchanged
Confidentiality impact
Low
Integrity impact
None
Availability impact
None

Weakness class (CWE)

CWE-269 · Improper Privilege Management

CVSS vector

CVSS:3.0/AV:N/AC:L/PR:L/UI:N/S:U/C:L/I:N/A:N

nvd-primary

Root cause

To simplify setup, a service account is granted broad, cluster-wide permissions. The principle of least privilege is skipped during installation.

The bug in code

The whole CWE-269 class

A representative example of this vulnerability class. Not the vendor's source code; it shows the faulty pattern and its fix.

Vulnerable

yaml
kind: ClusterRolerules:  - apiGroups: ["*"]    resources: ["*"]    verbs: ["*"]

Fixed

yaml
kind: Rolemetadata:  namespace: lodos-systemrules:  - apiGroups: ["apps"]    resources: ["deployments"]    verbs: ["get", "list", "update"]

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

  1. Fix✗ → ✓

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References

Show all references (1 more)

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

All records