CVE-2026-35188

5.0 MEDIUM 0.3% exploit odds Fix listed Memory safety Library

What it is

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.

At a glance

Exploitability: Can be exploited over the network with a low-privilege account. Limited direct impact.
Exploit odds: 0.3% chance of exploitation in the next 30 days (EPSS).
Fix: A patch, advisory or fixed version is referenced. Upgrade or apply it.

Timeline

2026-06-09 17:17 UTC PublishedDisclosed publicly on CVE.org and NVD
2026-07-23 08:10 UTC Last updatedMost recent change to the record

Why it ranks here

Exploited in the wild: no, CISA does not list it.
Exploit odds: 0.3% in the next 30 days (EPSS).
Severity: 5.0 MEDIUM (CVSS).
Fix: a patch or advisory is linked.

Details

Published: 2026-06-09 17:17 UTC
Last modified: 2026-07-23 08:10 UTC
Exploit probability: 0.3% · EPSS, next 30 days
Weakness: CWE-415
Record status: Analyzed

Affected

OpenSSL < 3.6.3
OpenSSL 4.0.0

Attack profile CVSS 3.1 · 5.0

Attack vector: Network
Complexity: High
Privileges needed: Low
User interaction: None
Scope: Unchanged
Confidentiality: Low
Integrity: Low
Availability: Low

Raw vector

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

Is it in your code?

Hand this to your coding agent. It searches your project for the affected products and checks versions. Nothing leaves your machine.

Read https://cve-list.com/agent/cve/CVE-2026-35188.md and follow it. Check whether this project is affected by CVE-2026-35188. Read only. Don't change anything and don't upload my code. Tell me yes, no or not sure, with the file as proof.

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Fix and advisories

References

NVD record · CVE.org record