Security readout for executives and security teams
Plain-English summary
CVE-2026-27613 affects TinyWeb web server versions before 2.01. Remote unauthenticated attackers may bypass CGI parameter protections. Depending on CGI configuration, impact can range from source code disclosure to remote code execution. Organizations using TinyWeb with CGI, especially PHP CGI, should treat this as urgent.
Executive priority
Prioritize remediation for internet-facing TinyWeb servers using CGI. The worst-case business impact is full server compromise or sensitive code disclosure, with no authentication required. Patch quickly, and apply compensating controls where immediate upgrade is not possible.
Technical view
TinyWeb before 2.01 has CGI parameter injection that bypasses STRICT_CGI_PARAMS and EscapeShellParam protections. The advisory maps this to CWE-78 and CWE-88 with CVSS 4.0 score 10.0. Risk depends on enabled CGI handling and the CGI executable’s command-line behavior. Version 2.01 contains the patch.
Likely exposure
Exposure is likely limited to systems running TinyWeb versions earlier than 2.01 with CGI enabled. Hosting interpreted CGI executables such as php-cgi.exe increases risk. TinyWeb deployments without CGI may have materially lower exposure, but sources do not provide a complete configuration matrix.
Exploitation context
Sources describe unauthenticated network exploitation potential and possible RCE or source disclosure. The provided data does not show CISA KEV listing or confirmed active exploitation. No safe conclusion can be made about exploitation in the wild from the supplied sources.
Researcher notes
The key research question is configuration dependency: CGI enabled, CGI executable type, and whether strict parameter handling is active. The vendor advisory and patch should be reviewed to understand exact parser behavior. Avoid assuming exploitability on non-CGI deployments without validation.
Mitigation direction
- Upgrade TinyWeb to version 2.01 or later.
- If immediate upgrade is impossible, ensure STRICT_CGI_PARAMS is enabled.
- Avoid CGI executables that accept dangerous command-line flags.
- For PHP CGI, consider WAF rules blocking risky query-string patterns.
- Review vendor advisory and release notes before changing production systems.
Validation and detection
- Inventory TinyWeb instances and confirm deployed version.
- Identify whether CGI support is enabled on each instance.
- Review CGI executables in use, especially php-cgi.exe.
- Confirm STRICT_CGI_PARAMS is enabled where upgrade is delayed.
- Verify TinyWeb 2.01 or later is deployed after remediation.
Public sources used
Generated from the cited source records. This long-tail analysis has not been individually reviewed by a named human.
Conservative CVE-to-ATT&CK context
These mappings and lookup hints may be relevant to the vulnerability behavior, CWE, affected product, or exposure path. Glexia-inferred context is not an official MITRE, ATT&CK, CWE, or CVE Program mapping.
ATT&CK lookup starting points
Use these exact CWE pages and searches to review the Glexia ATT&CK library from this CVE's weakness and description context.
CWE-78: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupCWE-88: Command execution behavior lookup
Command injection weaknesses can lead defenders to review execution techniques and command interpreter telemetry. Open the exact CWE lookup page first, then review the ATT&CK searches from that MITRE weakness context. This is a Glexia lookup hint, not an official ATT&CK mapping.
Open ATT&CK lookupExecution behavior lookup
The CVE wording references code or command execution, so execution technique review may help defensive triage. This is a Glexia inferred lookup path, not an official MITRE, ATT&CK, or CVE Program mapping.
Open ATT&CK lookupCVE-2026-27613 mapping review
Open the CVE-to-ATT&CK bridge for reviewed, inferred, or future official mappings tied to this CVE.
Open ATT&CK lookup- Severity
- Critical
- CVSS
- 10 (4.0)
- Known Exploited
- No
- Published
Vector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
CNA and ADP enrichment extracted from CVE v5
These fields come from the CVE record and ADP containers, not from Glexia's Take. They preserve time-varying source decisions such as CISA SSVC, KEV status, CVSS metrics, and provider references.
CVSS vector scores
1 official scoreWe collect every scored CVSS vector available in the official CNA and ADP containers. When more than one version is present, the table keeps the source vectors side by side instead of collapsing them into the highest score.
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H——Primary CVE scoreVulnerability scoring details
Base CVSS 4.0 score
10CriticalVector: CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:H/VI:H/VA:H/SC:H/SI:H/SA:H
Source materials
- CVE List V5 sourceCVE List V5
- https://github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-rfx5-fh9m-9jj9CVE reference · x_refsource_CONFIRM
- https://github.com/maximmasiutin/TinyWeb/commit/d9dbda8db49da69d2160e1c527e782b73b5ffb6bCVE reference · x_refsource_MISC
- https://github.com/maximmasiutin/TinyWeb/releases/tag/v2.01CVE reference · x_refsource_MISC
- https://www.masiutin.net/tinyweb-cve-2026-27613.htmlCVE reference · x_refsource_MISC
Products and packages named in the record
CWE details
CWE links open Glexia weakness intelligence pages with official CWE context, developer remediation guidance, and related CVE mappings.
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection')
Improper Neutralization of Special Elements used in an OS Command ('OS Command Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.
Improper Neutralization of Argument Delimiters in a Command ('Argument Injection')
Improper Neutralization of Argument Delimiters in a Command ('Argument Injection') represents a recurring weakness pattern that can create exploitable paths when design, validation, or implementation controls are missing.