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CVE-2026-35189

OpenSSL: Excessive Memory Allocation in Relative CRLDP Processing

OpenSSL OpenSSLLibraries & packages
Open in ThreatlineRecord JSON
CVSS
5.3Medium
ExploitationNo known exploitationNot in CISA KEV, which does not prove it is unexploitedCISA KEV
Exploit odds (EPSS)0.27%Chance of exploitation activity in the next 30 days, higher than 17% of CVEs. Scored 23 Oct 2026FIRST EPSS
Fixed in4.0.3Also 3.6.5, 3.5.9 and 4 moreCVE List
Published29 Sep 2026Updated 30 Sep 2026CVE List

What fixes it

Show all 7 fixed versions

A fixed version on one release line is not the upgrade target for every line. Check your exact version and any vendor backports.

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.

Text from CVE List

Affected versions 7

  • OpenSSLaffected: 4.0.0 before 4.0.3CVE List
  • OpenSSLaffected: 3.6.0 before 3.6.5CVE List
  • OpenSSLaffected: 3.5.0 before 3.5.9CVE List
  • OpenSSLaffected: 3.4.0 before 3.4.8CVE List
  • OpenSSLaffected: 3.0.0 before 3.0.23CVE List
  • OpenSSLaffected: 1.1.1 before 1.1.1zjCVE List
  • OpenSSLaffected: 1.0.2 before 1.0.2zsCVE List

References 5