Resource exhaustion in Yhirose Cpp-Httplib

CVE-2025-52887

cpp-httplib is a C++11 single-file header-only cross platform HTTP/HTTPS library. In version 0.21.0, when many http headers fields are passed in, the library does not limit the number of headers, and the memory associated with the headers will not be released when the connection is disconnected. This leads to potential exhaustion of system memory and results in a server crash or unresponsiveness. Version 0.22.0 contains a patch for the issue.

Vulnerability class: DoS (Denial of Service)

Published · last modified .

CVSS v3 metric

CVSS v3 base score 7.5 (High). Vector: CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H.

EPSS exploit prediction

EPSS: 0.005 (40.9th percentile), scored .

Very low probability of exploitation in the next 30 days; routine patching cadence is appropriate. 41st percentile — 40.9% of CVEs in the catalogue have a lower EPSS than this one. How to read EPSS.

EPSS trend (30 days)EPSS over the last 30 days for CVE-2025-52887: held from 0.005 to 0.005.

EPSS over last 30 days · oldest: 0.005 · newest: 0.005 · change: +0.000

Affected products

Weakness classification (CWE)

Public proof-of-concept exploits

References

Frequently asked questions

What is CVE-2025-52887?
CVE-2025-52887 is a high-severity vulnerability in Yhirose Cpp-Httplib, classified under Uncontrolled Resource Consumption. CVSS score: 7.5/10. Published 2025-06-26.
How severe is CVE-2025-52887?
High severity. CVSS v3 base score is 7.5 out of 10.
Is CVE-2025-52887 known to be exploited?
1 public proof-of-concept repositories are indexed. Not currently listed in the CISA KEV catalog.