CVE-2025-66630
Gofiber Fiber ≤ 2.52.11
Raw vector
CVSS:4.0/AV:N/AC:H/AT:N/PR:N/UI:N/VC:H/VI:H/VA:L/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:XSummary
CVE-2025-66630 is a critical-severity PRNG (CWE-338) vulnerability in Gofiber Fiber. Its CVSS base score is 9.2 (Critical).
Operationally, exploitation aligns with the MITRE ATT&CK technique Forge Web Credentials (T1606); ranked at the 39th percentile by exploit likelihood (below the median); it is not currently listed in the CISA KEV catalog.
The strongest mitigations our analysis identified map to SC-13 (Cryptographic Protection) and SA-8 (Security and Privacy Engineering Principles) — 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-2025-66630 affects Fiber, an Express-inspired web framework written in Go, specifically versions prior to 2.52.11 when running on Go versions before 1.24. The vulnerability stems from Fiber v2 UUID functions, such as utils.UUIDv4(), which fail to propagate errors from the underlying crypto/rand implementation. If secure randomness cannot be obtained, these functions silently return predictable, repeated, or low-entropy identifiers without alerting application code. This issue, classified under CWE-338 (use of cryptographically weak random number generator), has a CVSS v3.1 base score of 9.4 (AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:L) due to its potential impact on security-critical components.
Attackers can exploit this vulnerability remotely without authentication or user interaction by targeting applications using affected Fiber middleware, such as session management, CSRF protection, rate limiting, or request-ID generation, which default to the flawed UUIDv4(). In environments where crypto/rand errors occur—such as resource-constrained systems or misconfigured entropy sources—predictable identifiers enable attacks like session fixation or hijacking, CSRF bypasses, rate limit evasion, and request tracking or duplication. The high confidentiality and integrity impacts arise from attackers predicting or colliding with security tokens, potentially leading to unauthorized access or data manipulation.
Mitigation is available in Fiber version 2.52.11, which addresses the error-handling flaw in UUID functions. Security practitioners should upgrade to this version immediately, verify Go runtime compatibility (ideally 1.24 or later), and audit custom code relying on Fiber's UUID utilities. Official advisories, including the GitHub security advisory GHSA-68rr-p4fp-j59v, release notes for v2.52.11, and the fixing commit eb874b6f6c5896b968d9b0ab2b56ac7052cb0ee1, provide detailed patch information and reproduction steps.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-207191
Vulnerability Data
Fiber is an Express inspired web framework written in Go. Before 2.52.11, on Go versions prior to 1.24, the underlying crypto/rand implementation can return an error if secure randomness cannot be obtained. Because no error is returned by the Fiber…
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v2 UUID functions, application code may unknowingly rely on predictable, repeated, or low-entropy identifiers in security-critical pathways. This is especially impactful because many Fiber v2 middleware components (session middleware, CSRF, rate limiting, request-ID generation, etc.) default to using utils.UUIDv4(). This vulnerability is fixed in 2.52.11.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 3 hardening rules · 3 OS baselines
V7.2.3V11.5.1
Mitigating Controls (NIST 800-53 r5) AI
Requiring specific approved cryptography for protection directly mandates use of strong PRNGs instead of weak ones.
Engineering principles applied during design and development include selection of cryptographically strong random number generation.
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 explicitly require cryptographically strong RNG selection and usage in security contexts.
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.
Mandates use of approved cryptographic controls, directly requiring cryptographically strong RNGs.
Security testing can detect use of weak random number generators.
Secure SDLC processes should catch weak PRNG usage during design and code review.
Application security requirements can specify cryptographically strong random number generation.
Secure engineering principles include selection of appropriate cryptographic primitives.
Secure coding standards prohibit use of weak PRNGs in security contexts.
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 (1 rule)
- V-248563 The OL 8 SSH server must be configured to use strong entropy. prevents CWE-338
RHEL 8 (1 rule)
- V-230253 RHEL 8 must ensure the SSH server uses strong entropy. prevents CWE-338
Ubuntu 22.04 (1 rule)
- V-260650 Ubuntu 22.04 LTS must implement NIST FIPS-validated cryptography to protect classified information and for the following: To provision digital signatures, to generate cryptographic hashes, and to protect unclassified information requiring confidentiality and cryptographic protection in accordance with applicable federal laws, Executive Orders, directives, policies, regulations, and standards. prevents CWE-338