CVE-2026-29046
Ritlabs Tinyweb ≤ 2.04
Raw vector
CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:H/VA:L/SC:N/SI:H/SA:L/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:XSummary
CVE-2026-29046 is a critical-severity Improper Input Validation (CWE-20) vulnerability in Ritlabs Tinyweb. Its CVSS base score is 9.2 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 32th percentile by exploit likelihood (below the median); 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 CM-7 (Least Functionality) and SA-11 (Developer Testing and Evaluation) — 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-2026-29046 affects TinyWeb, a lightweight web server supporting HTTP and HTTPS, implemented in Delphi for Win32 platforms. In versions prior to 2.04, the server's request parser fails to strictly reject dangerous control characters such as CR, LF, and NUL in HTTP header lines and values, including encoded variants like %0d, %0a, and %00. These headers are subsequently mapped into CGI environment variables prefixed with HTTP_ , enabling header value confusion across parser boundaries and the injection of unsafe data into the CGI execution context. The vulnerability is rated 8.2 on the CVSS 3.1 scale (AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:H/A:L) and is associated with CWEs 20 (Improper Input Validation), 74 (Incorrect Conversion between Representations), 93 (Improper Neutralization of CRLF Sequences), and 114 (Process Control).
Remote attackers require no privileges or user interaction to exploit this issue over the network with low complexity. By crafting malicious HTTP requests with tainted headers containing control characters or their encodings, attackers can manipulate CGI environment variables, potentially leading to high integrity impacts such as arbitrary code execution, data tampering, or other injections within the CGI context, alongside limited availability disruption.
The vulnerability has been addressed in TinyWeb version 2.04. Security practitioners should upgrade to this patched release. Detailed patch information is available in the GitHub commit at https://github.com/maximmasiutin/TinyWeb/commit/53aa8b6e5146491d7be57920e3fc50d7a34e4d5a and the security advisory at https://github.com/maximmasiutin/TinyWeb/security/advisories/GHSA-r3gf-pg2c-m7mc.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-9972
Vulnerability Data
TinyWeb is a web server (HTTP, HTTPS) written in Delphi for Win32. Prior to version 2.04, TinyWeb accepts request header values and later maps them into CGI environment variables (HTTP_*). The parser did not strictly reject dangerous control characters in…
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header lines and header values, including CR, LF, and NUL, and did not consistently defend against encoded forms such as %0d, %0a, and %00. This can enable header value confusion across parser boundaries and may create unsafe data in the CGI execution context. This issue has been patched in version 2.04.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 14 hardening rules · 8 OS baselines
V1.2.1V1.2.3V1.2.5V1.2.8
Mitigating Controls (NIST 800-53 r5) AI
Least functionality directly restricts execution of commands or loading of libraries to only approved capabilities, stopping untrusted sources from being used.
Developer testing and evaluation can discover missing input validation through analysis or test cases.
Mobile code control explicitly defines and enforces acceptable sources and technologies for code/commands loaded at runtime.
SI-10 directly requires validity checks on information inputs, structurally preventing improper or missing validation.
Malicious code protection mechanisms block execution or loading of code from untrusted sources before it can run.
Policies and enforcement for user-installed software prevent introduction and execution of untrusted libraries or commands.
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.
Explicitly prevents execution of unauthorized software, directly blocking untrusted commands or libraries.
Secure SDLC practices directly require and enforce input validation during development.
Assessing authenticity/integrity before acquisition reduces use of untrusted sources for commands/libraries.
Hardened configuration baselines can enforce trusted paths and execution policies.
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.
Testing against a defined set of requirements and using code review plus vulnerability scanning forces validation of inputs and handling of unanticipated conditions, reducing the chance that malformed data will be accepted.
Logging supports detection of injection attempts but does not prevent the weakness.
Monitoring activities can identify active injection attacks after they occur.
Restricting software installation prevents loading untrusted libraries or executing commands from unknown sources.
Secure-coding guidelines and mandatory security testing (including code scans) compel developers to validate and sanitize inputs at design and implementation time, lowering the incidence of malformed or malicious data reaching downstream components.
Mandating input controls that include integrity checks and input validation ensures that untrusted data is examined before use, blocking the root cause of many injection and malformed-data weaknesses.
Hardening callouts derived
Configuration rules from DISA STIG baselines that bear on weaknesses of the type cited by this CVE. Each rule is shown with the relationship its mapping actually records, against the CWE it was authored against. Derived via CVE→CWE over `controls_xwalks` (authoritative rows only; rows rated `none` are excluded).
Oracle Linux 8 (3 rules)
- V-248568 OL 8 system commands must be owned by root. prevents CWE-114
- V-248567 OL 8 system commands must have mode 755 or less permissive. prevents CWE-114
- V-248569 OL 8 system commands must be group-owned by root or a system account. prevents CWE-114
RHEL 8 (1 rule)
- V-230265 RHEL 8 must prevent the installation of software, patches, service packs, device drivers, or operating system components of local packages without verification they have been digitally signed using a certificate that is issued by a Certificate Authority (CA) that is recognized and approved by the organization. prevents CWE-20
Windows 10 (1 rule)
- V-220828 The default autorun behavior must be configured to prevent autorun commands. prevents CWE-114
Windows 11 (1 rule)
- V-253387 The default autorun behavior must be configured to prevent autorun commands. prevents CWE-114
Windows Server 2016 (1 rule)
- V-224933 The default AutoRun behavior must be configured to prevent AutoRun commands. prevents CWE-114
Windows Server 2019 (1 rule)
- V-205805 Windows Server 2019 default AutoRun behavior must be configured to prevent AutoRun commands. prevents CWE-114
Windows Server 2022 (1 rule)
- V-254353 Windows Server 2022 default AutoRun behavior must be configured to prevent AutoRun commands. prevents CWE-114