Bug 2543242 (CVE-2026-35189)

Summary:	CVE-2026-35189 openssl: openssl: Denial of Service via excessive memory allocation in CRL distribution point processing
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	abarbaro, akhatavk, alizardo, anthomas, aos-team-art-private, asdas, csutherl, dpaolell, ehelms, ggainey, jchui, jclere, jdelft, jhe, jpasqual, jupierce, juwatts, ktsao, lgarciaa, mbiarnes, mdellweg, mhulan, nboldt, nmoumoul, oaljalju, osousa, pcreech, pjindal, plodge, ppalepu, ppostler, prdhamdh, psrna, rchan, rhel-process-autobot, sghai, sidsharm, smallamp, suppawar, szappis, tmalecek, vchlup, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A flaw was found in OpenSSL. A remote attacker can cause a Denial of Service (DoS) by presenting a specially crafted certificate during a Transport Layer Security (TLS) handshake. When OpenSSL processes and caches certificate extensions containing numerous Certificate Revocation List (CRL) distribution points, it allocates an excessive amount of memory. This disproportionate memory usage can exhaust system resources and crash the affected client or server application.	Story Points:	---
Clone Of:		Environment:
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-29 15:51:00 UTC

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.