Security Digest · Vulnerability record
CVE-2026-30877: baserCMS Update Functionality Vulnerable to OS Command Injection
baserCMS is a website development framework.
CVSS 9.1 Critical EPSS 2.1% · p81
Should you act?
Critical, preconditions apply
Severe if exploited, but exploitation needs conditions that may not apply to you. This signal is computed from CISA KEV, EPSS and CVSS data; it is not an editorial verdict.
- No confirmed exploitation. It is not in CISA’s KEV catalog and CISA’s SSVC assessment records no known exploitation. That can change quickly after a public write-up; re-check if you are affected.
- EPSS 2.1%, percentile 81: FIRST’s model estimates a 2.1% chance of exploitation activity in the next 30 days, higher than 81% of all scored CVEs (elevated). EPSS is a probability, not a verdict.
- Needs an account (high (admin)). Exposure depends on who can log in.
- Only applies if your dependency tree includes
baserproject/basercms(Composer (PHP)) <= 5.2.2, fixed in 5.2.3. Check your lockfile, including transitive dependencies.
What it is
baserCMS is a website development framework. Prior to version 5.2.3, there is an OS command injection vulnerability in the update functionality. Due to this issue, an authenticated user with administrator privileges in baserCMS can execute arbitrary OS commands on the server with the privileges of the user account running baserCMS. This issue has been patched in version 5.2.3.
From the GitHub advisory
Summary The latest version of baserCMS (basercms-5.2.2) contains an OS command injection vulnerability (CWE-78) in its update functionality. Due to this issue, an authenticated user with administrator privileges in baserCMS can execute arbitrary OS commands on the server with the privileges of the user account running baserCMS.
Details Please refer to the attached materials. OSコマンドインジェクション（baserCMSのアップデート機能）.pdf
Impact An authenticated user with administrator privileges in baserCMS can execute OS commands on the server with the privileges of the user account running baserCMS.
Weakness type: CWE-78.
Product: baserproject/basercms (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-03-31
Affected and fixed versions
| Ecosystem | Package | Vulnerable | First fixed |
|---|---|---|---|
| Composer (PHP) | baserproject/basercms | <= 5.2.2 | 5.2.3 |
| Vendor | Product | Affected versions (per CVE record) |
|---|---|---|
| baserproject | basercms | < 5.2.3 |
Severity scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| GitHub_M | 3.1 | 9.1 Critical | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
| GitHub | 3.1 | 9.1 | CVSS:3.1/AV:N/AC:L/PR:H/UI:N/S:C/C:H/I:H/A:H |
- Attack vector: network (remotely reachable)
- Attack complexity: low
- Privileges required: high (admin)
- User interaction: none
- Scope: changed (can affect other components)
CVSS measures how bad a flaw is if exploited, not how likely exploitation is. Read it next to the exploitation data below.
Exploitation and urgency
- CISA KEV: not listed (no confirmed in-the-wild exploitation known to CISA).
- CISA SSVC assessment: exploitation none, automatable no, technical impact total.
- FIRST EPSS (model of 2026-10-21): 2.06% probability of exploitation activity in the next 30 days; percentile 81.
Timeline
- — CVE record published by GitHub_M
- — GitHub-reviewed advisory GHSA-m9g7-rgfc-jcm7 published (critical)
- — CVE record last updated
Sources and references
Original sources first. Version and fix details should always be confirmed against the vendor or project advisory.
Vulnerability records
- GitHub Advisory GHSA-m9g7-rgfc-jcm7 github.com
- CVE.org record CVE-2026-30877 cve.org
- NVD entry CVE-2026-30877 nvd.nist.gov
Other references from the CVE record and advisory
- github.com github.com
- basercms.net basercms.net
- github.com github.com
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