Raw vector
CVSS:4.0/AV:N/AC:L/AT:P/PR:N/UI:N/VC:L/VI:L/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-2025-53628 is a medium-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Yhirose Cpp-Httplib. Its CVSS base score is 6.3 (Medium).
Operationally, exploitation aligns with the MITRE ATT&CK technique Network Denial of Service (T1498); ranked at the 36th 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 AC-10 (Concurrent Session Control) 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-2025-53628 affects cpp-httplib, a C++11 single-file header-only cross-platform HTTP/HTTPS library. In versions prior to 0.20.1, the library lacks a limit on the length of a unique line, such as in HTTP requests or responses, enabling attackers to trigger arbitrary memory allocation. This issue is classified under CWE-770 (Allocation of Resources Without Limits or Throttling), CWE-835, and CWE-444 (Inconsistent Interpretation of HTTP Requests), with a CVSS v3.1 base score of 8.8 (AV:N/AC:L/PR:N/UI:R/S:U/C:H/I:H/A:H). The vulnerability is fixed in version 0.20.1 and is related to CVE-2025-53629.
Remote attackers can exploit this vulnerability over the network with low complexity and no required privileges, though it necessitates user interaction, such as tricking a user into processing a malicious HTTP request or response via an application using the library. Successful exploitation allows arbitrary memory allocation, potentially leading to high-impact denial of service through resource exhaustion, as well as unauthorized access, modification, or disruption of data and system integrity.
The cpp-httplib security advisories (GHSA-j6p8-779x-p5pw, GHSA-qjmq-h3cc-qv6w) and the fixing commit (7b752106ac42bd5b907793950d9125a0972c8e8e) recommend upgrading to version 0.20.1, which introduces the necessary line length limits to prevent unbounded allocations. No additional workarounds are specified in the provided references.
OWASP Top 10 for Web (2025)
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2025-21053
Vulnerability Data
cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. Prior to 0.20.1, cpp-httplib does not have a limit for a unique line, permitting an attacker to explore this to allocate memory arbitrarily. This vulnerability is fixed in 0.20.1. NOTE:…
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This vulnerability is related to CVE-2025-53629.
- CWE(s)
Related Threats
MITRE ATT&CK Enterprise Techniques
CVEs Like This One
Affected Assets
Mitigating Controls
Control response
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- 5 hardening rules · 3 OS baselines
V4.1.3V4.2.4V1.5.3V4.1.1
Mitigating Controls (NIST 800-53 r5) AI
Directly enforces a hard limit on concurrent sessions, structurally preventing unbounded resource allocation.
Developer testing and evaluation can discover unreachable loop exit conditions through static analysis, fuzzing, or execution tracing.
Requires explicit allocation of resources by priority or quota, directly stopping unlimited allocation.
Flaw remediation processes identify and correct infinite-loop defects reported from testing or operations.
Imposes a limit on consecutive invalid attempts, preventing one specific class of unbounded resource consumption.
Requiring documented development processes and secure coding standards reduces introduction of loops whose termination conditions are unreachable.
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.
Monitoring capacity and taking action to maintain availability directly reduces unchecked resource allocation.
Configuration management can enforce uniform HTTP parsing rules across intermediaries, directly mitigating inconsistent interpretation.
Secure SDLC practices (reviews, testing, static analysis) directly prevent introduction of infinite-loop defects.
Network monitoring can detect smuggling attempts via anomalous HTTP traffic or logs, while eliminating the inconsistency directly aids detection of such events.
Static analysis and vuln scanning during asset assessment can detect unreachable loop exits.
Network protections can enforce consistent HTTP proxy/firewall behavior to block smuggling, and removing the weakness helps prevent unauthorized access via request smuggling.
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.
Baseline comparison of CPU, memory and bandwidth usage helps surface uncontrolled resource allocations before they cause service degradation.
Security testing can uncover infinite-loop conditions before release.
Capacity projections and elasticity measures ensure that allocation requests are bounded and can be throttled, reducing the window in which an attacker can force unbounded resource reservations.
Defining retention periods and deletion schedules for backup copies prevents indefinite accumulation of data on storage media without corresponding resource-management controls.
Architectural redundancy and automatic failover limit the impact of an attacker who forces excessive allocations, because spare capacity can absorb the load until the primary instance recovers.
Network security controls can enforce consistent HTTP parsing and proxy behavior that mitigates request smuggling.
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 (2 rules)
- V-248552 OL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770
- V-248553 OL 8 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-770
Oracle Linux 9 (2 rules)
- V-271710 OL 9 must be configured so that all network connections associated with SSH traffic are terminated after 10 minutes of becoming unresponsive. prevents CWE-770
- V-271709 OL 9 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770
RHEL 8 (1 rule)
- V-230244 RHEL 8 must be configured so that all network connections associated with SSH traffic terminate after becoming unresponsive. prevents CWE-770