CVE-2026-22799
Emlog ≤ 2.6.1
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/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:XCVSS and EPSS are reproduced from their sources (NVD, FIRST EPSS). Risk Priority is our own derived reading, not an NVD score.
Summary
CVE-2026-22799 is a critical-severity Unrestricted Upload of File with Dangerous Type (CWE-434) vulnerability in Emlog Emlog. Its CVSS base score is 9.3 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Web Shell (T1505.003); ranked in the top 46% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
The strongest mitigations our analysis identified map to SI-3 (Malicious Code Protection) and CM-7 (Least Functionality) — see the control section below for these in your framework.
Deeper analysis AI-assisted summary
Synthesised by an AI model from the NVD description and linked references — a reading aid, not an authoritative source.
CVE-2026-22799 is an unrestricted upload vulnerability in Emlog, an open source website building system, affecting versions 2.6.1 and earlier. The issue stems from the exposed REST API endpoint at /index.php?rest-api=upload, which handles media file uploads without proper validation of file types, extensions, or content. This flaw, mapped to CWE-434 (Unrestricted Upload of File with Dangerous Type), carries a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H) and was published on 2026-01-12.
Authenticated attackers with a valid API key or admin session cookie can exploit the endpoint to upload arbitrary files, including malicious PHP scripts, to the server. The API key may be obtained by gaining administrator access to enable the REST API setting or through separate information disclosure vulnerabilities in Emlog. Once uploaded, the PHP file can be executed to achieve remote code execution (RCE), resulting in full server compromise.
Mitigation details are provided in the GitHub security advisory at https://github.com/emlog/emlog/security/advisories/GHSA-p837-mrw9-5x5j and a patching commit at https://github.com/emlog/emlog/commit/429b02fda842254b9b9b39303e9161999c180560. Security practitioners should update to a patched version of Emlog, disable the REST API if unused, and audit for exposed API keys or admin credentials.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-1995
Vulnerability Data
Emlog is an open source website building system. emlog v2.6.1 and earlier exposes a REST API endpoint (/index.php?rest-api=upload) for media file uploads. The endpoint fails to implement proper validation of file types, extensions, and content, allowing authenticated attackers (with a…
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valid API key or admin session cookie) to upload arbitrary files (including malicious PHP scripts) to the server. An attacker can obtain the API key either by gaining administrator access to enable the REST API setting, or via information disclosure vulnerabilities in the application. Once uploaded, the malicious PHP file can be executed to gain remote code execution (RCE) on the target server, leading to full server compromise.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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V5.1.1
Mitigating Controls (NIST 800-53 r5) AI
Malicious-code protection at entry points blocks dangerous file types from being accepted and executed.
Least functionality restricts the file types and automatic processing capabilities the system will accept.
Mobile-code controls define, authorize, and block unacceptable uploaded code before automatic processing occurs.
Mitigating Controls (NIST CSF 2.0) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→CSF cross-walk (authority under review) — links open the control.
Restricting execution of unauthorized software directly blocks dangerous uploaded files from running.
Hardened configuration baselines can enforce allowed file types and processing rules.
Secure development practices include input validation and file-type restrictions that prevent this weakness.
Mitigating Controls (ISO/IEC 27001:2022 Annex A) AI
Derived directly from the weakness types (CWEs) cited in the NVD entry via our AI-authored CWE→ISO cross-walk (authority under review) — links open the control.
Configuration and acceptance testing verify that file-upload handling enforces allowed types and does not permit dangerous content to be stored or executed.