# CVE-2024-4603: Excessive time spent checking DSA keys and parameters

> Attackers can cause denial of service by supplying excessively long DSA keys to applications using specific OpenSSL validation functions.

- **Severity:** Medium 5.3 (`CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L`)
- **Exploited in the wild:** Not known
- **Login needed:** Not needed
- **Attackable:** Over the internet
- **Victim action needed:** Not needed
- **Fix available:** Yes
- **Published:** 16 May 2024
- **Updated:** 14 Oct 2024
- **Also known as:** ALPINE-CVE-2024-4603, AZL-42049, AZL-42058, AZL-42063, AZL-42694, AZL-42766, AZL-47684, AZL-78534, BELL-CVE-2024-4603, CLEANSTART-2026-RF04086, CLSA-2024-1735121358, DEBIAN-CVE-2024-4603, GHSA-85xr-ghj6-6m46, JLSEC-2026-250, OESA-2025-1326, OESA-2025-1327, SUSE-SU-2024:1789-1, UBUNTU-CVE-2024-4603, openSUSE-SU-2024:13992-1

## What is CVE-2024-4603?

CVE-2024-4603 is a medium-severity denial of service vulnerability in OpenSSL, published on 16 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: Checking excessively long DSA keys or parameters may be very
slow.

Impact summary: Applications that use the functions EVP_PKEY_param_check()
or EVP_PKEY_public_check() to check a DSA public key or DSA parameters may
experience long delays. Where the key or parameters that are being checked
have been obtained from an untrusted source this may lead to a Denial of
Service.

The functions EVP_PKEY_param_check() or EVP_PKEY_public_check() perform
various checks on DSA parameters. Some of those computations take a long time
if the modulus (`p` parameter) is too large.

Trying to use a very large modulus is slow and OpenSSL will not allow using
public keys with a modulus which is over 10,000 bits in length for signature
verification. However the key and parameter check functions do not limit
the modulus size when performing the checks.

An application that calls EVP_PKEY_param_check() or EVP_PKEY_public_check()
and supplies a key or parameters obtained from an untrusted source could be
vulnerable to a Denial of Service attack.

These functions are not called by OpenSSL itself on untrusted DSA keys so
only applications that directly call these functions may be vulnerable.

Also vulnerable are the OpenSSL pkey and pkeyparam command line applications
when using the `-check` option.

The OpenSSL SSL/TLS implementation is not affected by this issue.

The OpenSSL 3.0 and 3.1 FIPS providers are affected by this issue.

Weakness: CWE-834 (Excessive Iteration), CWE-606 (Unchecked Input for Loop Condition)

## Which versions are affected by CVE-2024-4603?


| Package | Ecosystem | Affected | Fixed in |
| --- | --- | --- | --- |
| `openssl-3` | SUSE:Linux Enterprise Module for Basesystem 15 SP5 | All versions | 3.0.8-150500.5.33.1 |
| `openssl-3` | openSUSE:Leap 15.5 | All versions | 3.0.8-150500.5.33.1 |
| `openssl-3` | openSUSE:Tumbleweed | All versions | 3.1.4-8.1 |

## How do I fix CVE-2024-4603?

Apply the vendor's patch.

## Is CVE-2024-4603 being exploited?

There is no known exploitation of CVE-2024-4603 in the wild and no public exploit code.

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2024-4603 and fix it if it is affected.

What it is: CVE-2024-4603 is a medium-severity denial of service vulnerability in OpenSSL, published on 16 May 2024. An attacker can exploit it over the internet without logging in, with no action from the victim.
Exploitation: There is no known exploitation of CVE-2024-4603 in the wild and no public exploit code.

Affected product: OpenSSL. 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-2024-4603/ (Markdown: https://insights.sbomify.com/CVE-2024-4603/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2024-4603
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2024-4603
- OSV: https://osv.dev/vulnerability/CVE-2024-4603

---
From sbomify Insights: https://insights.sbomify.com/CVE-2024-4603/
Summaries are generated and may contain mistakes; the official description above is the record.