# CVE-2026-22776: cpp-httplib vulnerable to a denial of service (DOS) using a zip bomb

> Attackers can cause denial of service in applications using cpp-httplib by sending compressed requests that expand to consume excessive memory.

- **Severity:** High 8.7 (`CVSS:4.0/AV:N/AC:L/AT:N/PR:N/UI:N/VC:N/VI:N/VA:H/SC:N/SI:N/SA:N`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 12 Jan 2026
- **Updated:** 12 Jan 2026
- **Also known as:** DEBIAN-CVE-2026-22776, GHSA-h934-98h4-j43q, UBUNTU-CVE-2026-22776

## What is CVE-2026-22776?

CVE-2026-22776 is a high-severity denial of service vulnerability in yhirose cpp-httplib, published on 12 Jan 2026. 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. Prior to version 0.30.1, a Denial of Service (DoS) vulnerability exists in cpp-httplib due to the unsafe handling of compressed HTTP request bodies (Content-Encoding: gzip, br, etc.). The library validates the payload_max_length against the compressed data size received from the network, but does not limit the size of the decompressed data stored in memory.

Weakness: CWE-409 (Improper Handling of Highly Compressed Data (Data Amplification))

## Which versions are affected by CVE-2026-22776?

It affects 1 product.


Products: Yhirose Cpp-Httplib.

## How do I fix CVE-2026-22776?

Upgrade to a fixed version.

## Is CVE-2026-22776 being exploited?

It is not confirmed as exploited in the wild, but public exploit code for CVE-2026-22776 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-2026-21428](https://insights.sbomify.com/CVE-2026-21428/): cpp-httplib has CRLF injection in http headers (high 7.7)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-22776 and fix it if it is affected.

What it is: CVE-2026-22776 is a high-severity denial of service vulnerability in yhirose cpp-httplib, published on 12 Jan 2026. 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-2026-22776 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-2026-22776/ (Markdown: https://insights.sbomify.com/CVE-2026-22776/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-22776
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-22776
- OSV: https://osv.dev/vulnerability/CVE-2026-22776

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From sbomify Insights: https://insights.sbomify.com/CVE-2026-22776/
Summaries are generated and may contain mistakes; the official description above is the record.