CVE-2026-27823: EGroupware has a Remote Code Execution Vulnerability

Should you act?

Normal patch cycle

No exploitation signal; fix it in your next routine update if you are affected. 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 1.0%, percentile 62: FIRST’s model estimates a 1.0% chance of exploitation activity in the next 30 days, higher than 62% of all scored CVEs (moderate). EPSS is a probability, not a verdict.
• Needs an account (low (any account)). Exposure depends on who can log in.
• Only applies if your dependency tree includes egroupware/egroupware (Composer (PHP)) >= 26.0.20251208, < 26.2.20260224, fixed in 26.2.20260224; egroupware/egroupware (Composer (PHP)) < 23.1.20260224, fixed in 23.1.20260224. Check your lockfile, including transitive dependencies.

What it is

A vulnerability has been identified in EGroupware that may lead to Remote Code Execution (RCE). The issue allows an authenticated attacker to execute arbitrary commands on the server. If user self-registration is enabled, the vulnerability may be exploitable without prior authentication. The vulnerability stems from improper authorization checks combined with a file write primitive and an arbitrary file read vulnerability, which together enable full system compromise. This has been patched in versions 26.2.20260224 and 23.1.20260224.

From the GitHub advisory

Summary A critical vulnerability has been identified in EGroupware that may lead to Remote Code Execution (RCE). The issue allows an authenticated attacker to execute arbitrary commands on the server. If user self-registration is enabled, the vulnerability may be exploitable without prior authentication.

The vulnerability stems from improper authorization checks combined with a file write primitive and an arbitrary file read vulnerability, which together enable full system compromise.

Details 1. Improper Authorization in SmallPartMediaRecorder::ajaxupload()

The vulnerability originates in:

EGroupware\SmallParT\Widgets\SmallPartMediaRecorder::ajaxupload()

Weakness type: CWE-285, CWE-22, CWE-94, CWE-639.

Product: egroupware/egroupware (Composer (PHP)) · Assigned by: GitHub_M · Published: 2026-07-20

Affected and fixed versions

Severity scores

• Attack vector: network (remotely reachable)
• Attack complexity: low
• Attack requirements: none
• Privileges required: low (any account)
• User interaction: none

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 yes, technical impact total.
• FIRST EPSS (model of 2026-10-21): 0.97% probability of exploitation activity in the next 30 days; percentile 62.

Timeline

• 2026-07-07 — GitHub-reviewed advisory GHSA-h9qx-v5xp-ph8p published (critical)
• 2026-07-20 — CVE record published by GitHub_M
• 2026-07-21 — 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

1. GitHub Advisory GHSA-h9qx-v5xp-ph8p github.com
2. CVE.org record CVE-2026-27823 cve.org
3. NVD entry CVE-2026-27823 nvd.nist.gov

Other references from the CVE record and advisory

1. github.com github.com

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