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

Q: Which TLS deployments are exposed to this issue?

Clients that receive certificates from malicious peers are exposed. Servers are also exposed when they solicit and process client certificates during TLS handshakes.

Q: What does an attacker need to exploit the issue?

The attacker needs to present a crafted certificate containing many nameRelativeToCRLIssuer CRL distribution points. The certificate can remain within the approximately 100 KiB peer-certificate size limit while causing several hundred MiB of resident-memory allocation.

Q: How can the impact be amplified?

Multiple concurrent TLS connections presenting similarly crafted certificates can produce similarly large allocations. This can create enough memory pressure to crash an affected client or server.

Q: Does this affect the OpenSSL FIPS module boundary?

No. The affected code is outside the FIPS module boundary.

Published Sep 29, 2026

Updated

Excessive Memory Allocation in Relative CRLDP Processing

Other sources

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

— Launchpad

Affected Software

11 affected componentsFixes available

OpenSSL OpenSSL

debian/openssl<=3.0.20-1~deb12u2, <=3.0.22-1~deb12u1, <=3.5.7-1~deb13u2, <=3.6.4-1

3.5.7-1~deb13u33.6.5-1

OpenSSL OpenSSL>=1.0.2<1.0.2zs

OpenSSL OpenSSL>=1.1.1<1.1.1zj

OpenSSL OpenSSL>=3.0.0<3.0.23

OpenSSL OpenSSL>=3.4.0<3.4.8

OpenSSL OpenSSL>=3.5.0<3.5.9

OpenSSL OpenSSL>=3.6.0<3.6.5

OpenSSL OpenSSL>=4.0.0<4.0.3

Microsoft azl3 openssl 3.3.7-6<3.3.7-7

3.3.7-7

Microsoft azl3 edk2 20240524git3e722403cd16-20<20240524git3e722403cd16-21

20240524git3e722403cd16-21

Remediation

Recommended actions to resolve this vulnerability, in priority order.

Upgrade
Upgrade debian/openssl to a version that resolves this vulnerability.
Fixed in 3.5.7-1~deb13u3Fixed in 3.6.5-1
Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 3.3.7-7
Upgrade
Upgrade to a fixed release to a version that resolves this vulnerability.
Fixed in 20240524git3e722403cd16-21

Event History

Sep 29, 2026

CVE Published

via MITRE·03:32 PM

Data Sourced

via MITRE·03:32 PM

DescriptionWeakness

Data Sourced

via NVD·04:17 PM

RemedyDescriptionSeverityWeaknessAffected Software

Oct 3, 2026

Data Sourced

via Microsoft·08:17 AM

DescriptionSeverityWeaknessAffected Software

Frequently Asked Questions

Which TLS deployments are exposed to this issue?

Clients that receive certificates from malicious peers are exposed. Servers are also exposed when they solicit and process client certificates during TLS handshakes.

What does an attacker need to exploit the issue?

The attacker needs to present a crafted certificate containing many nameRelativeToCRLIssuer CRL distribution points. The certificate can remain within the approximately 100 KiB peer-certificate size limit while causing several hundred MiB of resident-memory allocation.

How can the impact be amplified?

Multiple concurrent TLS connections presenting similarly crafted certificates can produce similarly large allocations. This can create enough memory pressure to crash an affected client or server.

Does this affect the OpenSSL FIPS module boundary?

No. The affected code is outside the FIPS module boundary.

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

Other sources

Affected Software

Remediation

Event History

Frequently Asked Questions

Which TLS deployments are exposed to this issue?

What does an attacker need to exploit the issue?

How can the impact be amplified?

Does this affect the OpenSSL FIPS module boundary?

Company

Resources

Contact