Double-free When Checking OCSP Stapled Response (OpenSSL OpenSSL)

CVE-2026-35188
MEDIUM 5.0

At a glance

Source
NVD
EPSS
EPSS 0.30 % · percentile 23 ()
State
PUBLISHED
Published
Updated
Assigner
openssl
NVD status
Analyzed

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.

Weaknesses (CWE)

References

Scores

VersionScoreVectorScored by
CVSS 3.1MEDIUM 5.0CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:LCISA-ADP
CVSS 3.1MEDIUM 5.0CVSS:3.1/AV:N/AC:H/PR:L/UI:N/S:U/C:L/I:L/A:LNVD · 134c704f-9b21-4f2e-91b3-4a467353bcc0 (Secondary)

European references

CERT-FR advisories

Affected configurations (NVD CPE)

Affected products

ProductVersions
OpenSSL · OpenSSLaffected 4.0.0 < 4.0.1 ; affected 3.6.0 < 3.6.3

Sources

SourceLicence
CVE List (CVEProject cvelistV5)CVE Program Terms of Use
EPSS (FIRST.org)FIRST — attribution requested
ENISA EUVDENISA — reproduction authorised, source acknowledged
CERT-FR (ANSSI)Licence Ouverte / Etalab 2.0
NVD (NIST) via fkie-cad/nvd-json-data-feedsPublic domain — this product uses data from the NVD API but is not endorsed or certified by the NVD