CVE-2026-35188

EUVD-2026-35480
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.
ProviderTypeBase ScoreAtk. VectorAtk. ComplexityPriv. RequiredVector
opensslCNA
UNKNOWN
---
Base Score
CVSS 3.x
EPSS Score
Percentile: Unknown
Early Detection
Affected products identified ahead of NVD analysis through intelligence sources.
VendorProductVersionSource
opensslopenssl
4.0.0 ≤
𝑥
< 4.0.1
CNA
opensslopenssl
3.6.0 ≤
𝑥
< 3.6.3
CNA
Debian logo
Debian Releases
Debian Product
Codename
openssl
bookworm
3.0.20-1~deb12u1
fixed
bookworm (security)
3.0.20-1~deb12u2
fixed
bullseye
1.1.1w-0+deb11u1
fixed
bullseye (security)
1.1.1w-0+deb11u7
fixed
forky
vulnerable
sid
vulnerable
trixie
3.5.6-1~deb13u1
fixed
trixie (security)
3.5.6-1~deb13u2
fixed
Ubuntu logo
Ubuntu Releases
Ubuntu Product
Codename
openssl
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
questing
not-affected
resolute
not-affected
trusty
not-affected
xenial
not-affected
openssl-fips
jammy
not-affected
noble
not-affected
questing
dne
resolute
dne
openssl1.0
bionic
not-affected
jammy
dne
noble
dne
questing
dne
resolute
dne
nodejs
bionic
not-affected
focal
not-affected
jammy
needed
noble
not-affected
questing
not-affected
resolute
not-affected
trusty
not-affected
edk2
bionic
not-affected
focal
not-affected
jammy
not-affected
noble
not-affected
questing
not-affected
resolute
not-affected