# CVE-2026-35189: Excessive Memory Allocation in Relative CRLDP Processing

> A crafted certificate can cause excessive memory allocation during TLS handshakes, leading to denial of service in OpenSSL clients or servers.

- **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:** 29 Sep 2026
- **Updated:** 30 Sep 2026
- **Also known as:** ALPINE-CVE-2026-35189, AZL-105357, AZL-105447, AZL-105474, AZL-105513, AZL-105564, AZL-105627, AZL-105720, AZL-105819, AZL-105870, AZL-105900, AZL-105903, BELL-CVE-2026-35189, CLEANSTART-2026-RV52446, DEBIAN-CVE-2026-35189, ECHO-312d-f531-8c85, GHSA-3r46-fh9h-qv77, MINI-v4w2-99pq-3fqc, UBUNTU-CVE-2026-35189

## What is CVE-2026-35189?

CVE-2026-35189 is a medium-severity denial of service vulnerability in Openssl Openssl, published on 29 Sep 2026. An attacker can exploit it over the internet without logging in, with no action from the victim.

### Official description

Issue summary: A certificate with many nameRelativeToCRLIssuer CRL
distribution points causes disproportionate heap growth when OpenSSL caches
X.509 extensions.

Impact summary: Receiving a crafted certificate from a malicious peer can lead
to significant memory pressure and possible Denial of Service in clients or
in servers that solicit client certificates.

CWE: CWE-770: Allocation of Resources Without Limits or Throttling

Description: A certificate or a set of certificates that fits under the limit for
size of certificates accepted from the peer (~100 KiB) can result in allocation
of several hundred MiB of resident memory on the receiving side
during a normal TLS handshake.  This may be enough to crash the client or
server, if multiple concurrent connections lead to similarly large memory
allocations.

The fix postpones processing of the CRL distribution points extensions in
certificates to the time when the processed value is required for CRL processing.
This avoids keeping large memory allocations for a long time when such
certificates are received.

FIPS impact: no
The affected code is outside the FIPS module boundary.

Weakness: CWE-770 (Allocation of Resources Without Limits or Throttling)

## Which versions are affected by CVE-2026-35189?

It affects 1 product.


Products: Openssl Openssl.

## How do I fix CVE-2026-35189?

Apply the vendor's patch.

## Is CVE-2026-35189 being exploited?

There is no known exploitation of CVE-2026-35189 in the wild and no public exploit code.

## Other vulnerabilities in Openssl Openssl

- [CVE-2009-3245](https://insights.sbomify.com/CVE-2009-3245/): Null dereference in n/a (critical 10.0)
- [CVE-2006-3738](https://insights.sbomify.com/CVE-2006-3738/): Memory corruption in n/a (critical 10.0)
- [CVE-2026-63073](https://insights.sbomify.com/CVE-2026-63073/): Untrusted Sender DN Used as Format String in CMP Response Validation (critical 9.8)
- [CVE-2016-6309](https://insights.sbomify.com/CVE-2016-6309/): Use after free in n/a (critical 9.8)
- [CVE-2016-0799](https://insights.sbomify.com/CVE-2016-0799/): Integer overflow in n/a (critical 9.8)

## Fix prompt for AI coding agents

```text
Check this codebase for CVE-2026-35189 and fix it if it is affected.

What it is: CVE-2026-35189 is a medium-severity denial of service vulnerability in Openssl Openssl, published on 29 Sep 2026. 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-2026-35189 in the wild and no public exploit code.

Affected product: Openssl 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-2026-35189/ (Markdown: https://insights.sbomify.com/CVE-2026-35189/index.md)
```

## Sources

- CVE record: https://www.cve.org/CVERecord?id=CVE-2026-35189
- NVD: https://nvd.nist.gov/vuln/detail/CVE-2026-35189
- OSV: https://osv.dev/vulnerability/CVE-2026-35189

---
From sbomify Insights: https://insights.sbomify.com/CVE-2026-35189/
Summaries are generated and may contain mistakes; the official description above is the record.