CVE-2023-38039
Published: 15 September 2023
Summary
CVE-2023-38039 is a high-severity Allocation of Resources Without Limits or Throttling (CWE-770) vulnerability in Fedoraproject Fedora. Its CVSS base score is 7.5 (High).
Operationally, ranked in the top 5.4% of CVEs by exploit likelihood; it is not currently listed in the CISA KEV catalog; a public proof-of-concept is referenced.
Deeper analysis
CVE-2023-38039 affects curl and its libcurl component. When processing an HTTP response, curl stores incoming headers for later access via the headers API but imposes no limit on the number or total size of those headers. A remote server can therefore send an unbounded stream of headers, exhausting heap memory and triggering a denial-of-service condition. The flaw is tracked as CWE-770 and carries a CVSS 3.1 score of 7.5.
An attacker who controls or can influence an HTTP server reachable by a curl client can exploit the issue simply by returning an endless sequence of headers in a response. No authentication or user interaction is required, and the attack results in heap-memory exhaustion on the client, terminating the transfer or crashing the application.
The EPSS score has remained stable near 0.15 with no material post-disclosure climb from a low baseline.
EU & UK References
- 🇪🇺 ENISA EUVD: EUVD-2023-41865
Vulnerability details
When curl retrieves an HTTP response, it stores the incoming headers so that they can be accessed later via the libcurl headers API. However, curl did not have a limit in how many or how large headers it would accept…
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in a response, allowing a malicious server to stream an endless series of headers and eventually cause curl to run out of heap memory.
- CWE(s)
Related Threats
No named actor attribution yet. ATT&CK technique mapping in progress for this CVE.
Affected Assets
Mitigating Controls
Likely Mitigating Controls AI
Per-CVE control mapping for this CVE has not run yet; the list below is derived from the weakness types (CWEs) cited in the NVD entry.
This control implements explicit throttling on session allocation, addressing the weakness of allocating resources without limits.
Plan testing exercises resource allocation limits and throttling during simulated failures, directly addressing weaknesses that allow unbounded resource use.
Contingency plan updates ensure recovery strategies address unbounded resource allocation, making it harder for attackers to exploit lack of throttling to cause prolonged outages.
Provides continuity when unbounded resource allocation at the primary site leads to exhaustion and downtime.
Alternate services allow operations to continue when primary allocation of resources lacks limits or throttling.
Explicit planning of security-related actions requires defining limits, windows, and resource allocations, making allocation without throttling far less likely.
Measures of performance include tracking allocation behavior and throttling effectiveness, reducing the window for resource exhaustion attacks.
Imposes an inactivity-based limit on network resource allocation, throttling the number of concurrently held connections.