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NVD / CVE Program· CNA GitHub_M

CVE-2026-30879: baserCMS: Cross-site scripting vulnerability in blog post

Noroxi assessment

Priority: Monitor (action score 27/100)

  • 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: 0.24% (FIRST EPSS).
  • 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 CISA the attack is automatable: targets can be found by mass scanning.
  • Fixed version: baserproject basercms 5.2.3.

Low priority for now. Upgrade to baserproject basercms 5.2.3 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

baserCMS is a website development framework. Prior to version 5.2.3, baserCMS has a cross-site scripting vulnerability in blog posts. This issue has been patched in version 5.2.3.

MediumCVSS 6.9 · v4.0—No exploit Fix available
Published
Mar 30, 2026
Updated
Jun 17, 2026
EPSS
0.2% · 15th percentile

Report tools

JSON

Action score

27

Monitor

Low priority for now.

CVSS
27 / 40 · 6.9 / 10
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.2%

CISA SSVC decision

Exploitation
none
Automatable
yes
Technical impact
partial

Vulnrichment: CISA's decision-tree inputs.

CNA vs NVD score

NVD
—
CNA · GitHub_M
6.9
NVD has not scored this yet; the score shown is the CNA’s.

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N

The score given by the assigning authority versus NVD’s independent score. A gap means the severity is contested.

Get told when this record changes

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

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

Follow CVE-2026-30879

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
basercmsbasercms

Limit the impact of XSS

This is a cross-site scripting (XSS) vulnerability. A well-configured Content-Security-Policy doesn't fix it, but greatly reduces its impact. Check your site's CSP and other security headers for free.

Check security headers

Affected versions

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

  • basercms basercmsbefore 5.2.3

Versions reported by the vendor

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

  • baserproject basercms

    • < 5.2.3affected

Package-level exposure

OSV and GitHub Advisory data: ecosystem, package and range. SBOM matching uses this table.

EcosystemPackageAffected rangeFix
Packagistbaserproject/basercmsbefore 5.2.35.2.3

Same product

basercms: all records

Other highest-scoring records for the same primary product.

  • CVE-2017-10842SQL injection vulnerability in the baserCMS 3.0.14 and earlier, 4.0.5 and earlier allows remote attackers to execute arbitrary SQL commands
    40Plan
  • CVE-2023-43792baserCMS Code Injection Vulnerability in Mail Form Feature
    39Monitor
  • CVE-2023-43649baserCMS CSRF vulnerability in Content preview Feature
    39Monitor

Published before and after this one in the same product

  • ← EarlierCVE-2026-30877Mar 30, 2026 · baserCMS: OS Command Injection in the baserCMS Update Functionality
    28Monitor
  • ← EarlierCVE-2026-30878Mar 30, 2026 · baserCMS: Mail Form Acceptance Bypass via Public API
    21Monitor
  • Later →CVE-2026-30880Mar 30, 2026 · baserCMS: OS command injection vulnerability in installer
    37Monitor

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
baserproject basercms5.2.3 · descriptionVendor (CNA)
Packagist:baserproject/basercms5.2.3Package registry (OSV)

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.

  • CVE-2026-327340 days apartbaserCMS: Multiple vulnerabilities in baserCMS
    24Monitor
  • CVE-2024-46995522 days apartbaserCMS has Cross-site Scripting Vulnerability in HTTP 400 Bad Request
    24Monitor
  • CVE-2024-46994522 days apartbaserCMS has Cross-site Scripting Vulnerability in Blog posts and Contents list Feature
    21Monitor
  • CVE-2024-46996522 days apartbaserCMS has a Cross-site Scripting (XSS) Vulnerability in Blog posts Feature
    21Monitor
  • CVE-2024-46998522 days apartbaserCMS has a Cross-site Scripting (XSS) Vulnerability in Edit Email Form Settings Feature
    21Monitor

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
Integrity
Availability
Attack vector
Network
Attack complexity
Low
Privileges required
None
User interaction
None
Scope
X

Weakness class (CWE)

CWE-79 · Improper Neutralization of Input During Web Page Generation ('Cross-site Scripting')

CVSS vector

CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:L/VI:L/VA:L/SC:N/SI:N/SA:N/E:X/CR:X/IR:X/AR:X/MAV:X/MAC:X/MAT:X/MPR:X/MUI:X/MVC:X/MVI:X/MVA:X/MSC:X/MSI:X/MSA:X/S:X/AU:X/R:X/V:X/RE:X/U:X

nvd-secondary

Root cause

User content is inserted into the page as HTML. The browser interprets the content as code rather than data.

The bug in code

The whole CWE-79 class

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

Vulnerable

ts
commentEl.innerHTML = comment.body;

Fixed

ts
commentEl.textContent = comment.body;

Attack context

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

ATT&CK techniques

—

Change log

  1. Fix✗ → ✓

For records you follow, these changes also arrive as notifications. →

References

Show all references (2 more)

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

All records