CVE-2026-35189

What it is

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.

At a glance

Exploitability

Can be exploited over the network without logging in. Limited direct impact.

Exploit odds

0.3% chance of exploitation in the next 30 days (EPSS).

Fix

A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

1. 2026-09-29 16:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2. 2026-10-08 01:01 UTC Last updatedMost recent change to the record

Why it ranks here

• Exploited in the wild: no, CISA does not list it.
• Exploit odds: 0.3% in the next 30 days (EPSS).
• Severity: 5.3 MEDIUM (CVSS).
• Fix: a patch or advisory is linked.

Details

Published

2026-09-29 16:17 UTC

Last modified

2026-10-08 01:01 UTC

Exploit probability

0.3% · EPSS, next 30 days

Weakness

CWE-770 · Allocation without limits

Record status

Analyzed

Affected

• OpenSSL < 1.0.2zs
• OpenSSL < 1.1.1zj
• OpenSSL < 3.0.23
• OpenSSL < 3.4.8
• OpenSSL < 3.5.9
• OpenSSL < 3.6.5
• OpenSSL < 4.0.3

Attack profile CVSS 3.1 · 5.3

Attack vector

Network

Complexity

Low

Privileges needed

None

User interaction

None

Scope

Unchanged

Confidentiality

None

Integrity

None

Availability

Low

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-35189.md and follow it. Check whether this project is affected by CVE-2026-35189. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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