# CVE-2025-52887: cpp-httplib has unlimited number of http header fields, which causes memory leak

> Attackers can exhaust system memory by sending unlimited HTTP headers, causing server crashes or unresponsiveness in applications using this C++ library.

- **Severity:** High 7.5 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 26 Jun 2025
- **Updated:** 26 Jun 2025
- **Also known as:** GHSA-xjhg-gf59-p92h, OESA-2025-1721, OESA-2025-1722, OESA-2025-1723, OESA-2025-1724, OESA-2025-1829, UBUNTU-CVE-2025-52887

## What is CVE-2025-52887?

CVE-2025-52887 is a high-severity denial of service vulnerability in yhirose cpp-httplib, published on 26 Jun 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

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.

Weakness: CWE-400 (Uncontrolled Resource Consumption)

## Which versions are affected by CVE-2025-52887?

It affects 1 product.


Products: Yhirose Cpp-Httplib.

## How do I fix CVE-2025-52887?

Upgrade to a fixed version.

## Is CVE-2025-52887 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-52887 exists.

## Other vulnerabilities in yhirose cpp-httplib

- [CVE-2025-66570](https://insights.sbomify.com/CVE-2025-66570/): cpp-httplib Untrusted HTTP Header Handling: Internal Header Shadowing (REMOTE*/LOCAL*) (critical 10.0)
- [CVE-2026-45372](https://insights.sbomify.com/CVE-2026-45372/): cpp-httplib: HTTP header value percent-decoding in server-side `parse_header` enables CRLF injection (critical 9.9)
- [CVE-2026-46527](https://insights.sbomify.com/CVE-2026-46527/): Null dereference in cpp-httplib (high 8.7)
- [CVE-2026-32627](https://insights.sbomify.com/CVE-2026-32627/): cpp-httplib has a Silent TLS Certificate Verification Bypass on HTTPS Redirect via Proxy (high 8.7)
- [CVE-2026-22776](https://insights.sbomify.com/CVE-2026-22776/): cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb (high 8.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2025-52887 and fix it if it is affected.

What it is: CVE-2025-52887 is a high-severity denial of service vulnerability in yhirose cpp-httplib, published on 26 Jun 2025. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: It is not confirmed as exploited in the wild, but public exploit code for CVE-2025-52887 exists.

Affected product: yhirose cpp-httplib. No package-level version data is available, so check the vendor advisory linked from the reference page.

Task:
1. Search the dependency manifests and lockfiles (for example package.json, package-lock.json, requirements.txt, poetry.lock, uv.lock, pom.xml, build.gradle, go.mod, Cargo.lock, Gemfile.lock) and any Dockerfiles for the affected packages, including transitive dependencies.
2. If an affected version is in use, upgrade it to the fixed version for its release line with the project's package manager, so the lockfile is regenerated. Prefer the smallest upgrade that fixes it.
3. If there is no fix, or the upgrade would break the build, do not guess: explain the risk and the safest workaround instead.
4. Run the tests and summarise what changed and why.
5. If nothing in the project is affected, say so and change nothing.

Reference: https://insights.sbomify.com/CVE-2025-52887/ (Markdown: https://insights.sbomify.com/CVE-2025-52887/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2025-52887
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2025-52887
- OSV: https://osv.dev/vulnerability/CVE-2025-52887

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From sbomify Insights: https://insights.sbomify.com/CVE-2025-52887/
Summaries are generated and may contain mistakes; the official description above is the record.