Medium severity · published Sep 29, 2026
CVE-2026-35189
Excessive Memory Allocation in Relative CRLDP Processing
5.3
CVSS
0.3%
EPSS
No
On KEV
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.
CVSS vector
CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:L
Attack vector
Network
Complexity
Low
Privileges
None
User interaction
None
Confidentiality
None
Integrity
None
Availability
Low
Scope
Unchanged
Exploitation
Is it being used?
Exploit prediction (EPSS)0.3% · higher than 24% of CVEs
Exploited in the wildNo evidence yet
CISA KEVNot listed
Ransomware campaign useNot known
Affected products
Which versions
OP
OpenSSL · OpenSSL
4.0.0 before 4.0.3; 3.6.0 before 3.6.5; 3.5.0 before 3.5.9; 3.4.0 before 3.4.8; 3.0.0 before 3.0.23; 1.1.1 before 1.1.1zj; +1 more · source: vendor, NVD
References
NVD
https://nvd.nist.gov/vuln/detail/CVE-2026-35189
CVE.org
https://www.cve.org/CVERecord?id=CVE-2026-35189
vendor-advisory
https://openssl-library.org/news/secadv/20260929.txt
patch
https://github.com/openssl/openssl/commit/2b93c73b2c70ddc4c61c5e4bfaaa6bd71379eb84
patch
https://github.com/openssl/openssl/commit/8e0efc7549b7ff8246d40e585e3fd604f728473f
patch
https://github.com/openssl/openssl/commit/3842516cc15e8b2cf55747011045e77547e71d89
patch
https://github.com/openssl/openssl/commit/c72ae182cac17a82e4246c6ecd4e9c4ec3586ec9
More from OpenSSL
7.5
CVE-2014-0160
OpenSSL Information Disclosure Vulnerability
9.8
CVE-2026-63073
Untrusted Sender DN Used as Format String in CMP Response Validation
9.8
CVE-2026-31789
Heap Buffer Overflow in Hexadecimal Conversion
9.8
CVE-2022-2274
RSA implementation bug in AVX512IFMA instructions
9.8
CVE-2021-3711
SM2 Decryption Buffer Overflow
