CVE-2026-3633
Redhat Enterprise Linux 10.0 … 9.0
Raw vector
CVSS:3.1/AV:N/AC:H/PR:H/UI:R/S:U/C:L/I:L/A:LSummary
CVE-2026-3633 is a low-severity CRLF Injection (CWE-93) vulnerability in Redhat Enterprise Linux. Its CVSS base score is 3.9 (Low).
Operationally, exploitation aligns with the MITRE ATT&CK technique Exploit Public-Facing Application (T1190); ranked at the 13th 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 SI-10 (Information Input Validation) and SI-2 (Flaw Remediation) — see the control section below for these in your framework.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2026-12560
Vulnerability Data
A flaw was found in libsoup. A remote attacker, by controlling the method parameter of the `soup_message_new()` function, could inject arbitrary headers and additional request data. This vulnerability, known as CRLF (Carriage Return Line Feed) injection, occurs because the method…
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value is not properly escaped during request line construction, potentially leading to HTTP request injection.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise TechniquesAI
Why these techniques?
CRLF injection in HTTP request construction directly enables remote exploitation of applications using the vulnerable library.
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
Mitigating Controls (NIST 800-53 r5) AI
Directly requires validation and sanitization of untrusted input (method parameter) to soup_message_new to block CRLF sequences and resulting header injection.
Mandates prompt remediation of the identified flaw in libsoup so that method values are properly escaped before request-line construction.
Boundary-protection devices can be configured to inspect and drop HTTP requests containing injected CRLF/header content originating from the vulnerable library.
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.
Secure SDLC practices directly require input neutralization and validation to block CRLF injection.
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.
Security testing can detect CRLF flaws but does not itself implement the neutralization.
Secure development lifecycle mandates input validation and output encoding that directly prevents CRLF injection.
Application security requirements include rules for neutralizing special characters such as CRLF in inputs.
Secure architecture principles encourage safe handling of untrusted data but do not prescribe specific CRLF controls.
Secure coding standards explicitly require neutralization of CRLF sequences, fully addressing this weakness.