CVE & CISA-KEV Catalog

CVE-2026-35188

MEDIUM
5.0
CVSS v3
NVD

Description

Issue summary: A malicious server can exploit TLS OCSP stapling by delivering a crafted response through the status_request extension, triggering a double-free in the client's certificate verification path. Impact summary: Successful exploitation allows an attacker to corrupt heap memory via a double-free, potentially leading to a Denial of Service or possibly an attacker controlled code execution or other undefined behavior. If OCSP stapling is enabled and the TLS client connects to a malicious server, a crafted OCSP stapled response can trigger a double free in the TLS client when the stapled response is checked. The OCSP stapling is not enabled by default. Reliable code execution through a double-free is technically complex and highly environment-dependent but the Denial of Service impact is straightforward to achieve, warranting Moderate severity. No FIPS modules are affected by this issue as the affected code is outside the OpenSSL FIPS module boundary.

How to fix

Remediation Available
opensslDebian
Fixed in:3.6.3-1CVE-2026-35188

TridentStack Control can deploy fixes like this automatically across your Windows, macOS, and Linux fleet. See how it works

Remediation is compiled from vendor and distribution security advisories. Always confirm against the linked source for your exact version and platform.

CVSS v3 Vector

Exploitability

Attack VectorNetwork
Attack ComplexityHigh
Privileges RequiredLow
User InteractionNone
ScopeUnchanged

Impact

ConfidentialityLow
IntegrityLow
AvailabilityLow

CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:L

Exploit Intelligence

0.30%probability of exploitation in 30 days
22ndpercentile

Low risk: more likely to be exploited than 22% of all known CVEs.

References

Related Vulnerabilities

Other CWE-415 vulnerabilities, ordered by exploit likelihood. View all

CVESeverityCVSSEPSSExploitedFix
CVE-2023-25136Medium6.590%-Fix
CVE-2003-0545Critical9.887%-Fix
CVE-2018-0101Critical10.087%-Fix
CVE-2026-33824Critical9.873%KEVFix
CVE-2019-3829Medium5.359%-Fix
CVE-2021-3407Medium5.550%-Fix

Common questions

How do I fix CVE-2026-35188?

Upgrade openssl on debian unstable to 3.6.3-1 or later.

Is CVE-2026-35188 being actively exploited?

Not that we know of. CVE-2026-35188 is not in the CISA Known Exploited Vulnerabilities catalog. Its EPSS score of 0.30% is the estimated probability that it will be exploited in the next 30 days. That is higher than 22% of all scored CVEs.

How severe is CVE-2026-35188?

CVE-2026-35188 has a CVSS v3 base score of 5.0, rated moderate. CVSS rates the technical impact if the vulnerability is exploited, not how likely that is, so weigh it alongside the exploit-prediction score when you decide what to patch first.

What does CVE-2026-35188 affect?

Published advisories record a fix for openssl (Debian). Only products with a sourced advisory are listed, so treat this as what we can cite rather than a complete inventory.

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This product uses NVD data but is not endorsed or certified by the NVD. EPSS scores courtesy of FIRST.org (https://www.first.org/epss). Source: CISA KEV Catalog. Data as of 2026-07-23.