CVE-2026-35188

NameCVE-2026-35188
DescriptionIssue 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.
SourceCVE (at NVD; CERT, ENISA, LWN, oss-sec, fulldisc, Debian ELTS, Red Hat, Ubuntu, Gentoo, SUSE bugzilla/CVE, GitHub advisories/code/issues, web search, more)
Debian Bugs1139674

Vulnerable and fixed packages

The table below lists information on source packages.

Source PackageReleaseVersionStatus
openssl (PTS)bullseye1.1.1w-0+deb11u1fixed
bullseye (security)1.1.1w-0+deb11u8fixed
bookworm3.0.20-1~deb12u1fixed
bookworm (security)3.0.20-1~deb12u2fixed
trixie3.5.6-1~deb13u1fixed
trixie (security)3.5.6-1~deb13u2fixed
forky, sid3.6.3-1fixed

The information below is based on the following data on fixed versions.

PackageTypeReleaseFixed VersionUrgencyOriginDebian Bugs
opensslsourcebullseye(not affected)
opensslsourcebookworm(not affected)
opensslsourcetrixie(not affected)
opensslsource(unstable)3.6.3-11139674

Notes

[trixie] - openssl <not-affected> (Vulnerable code not present)
[bookworm] - openssl <not-affected> (Vulnerable code not present)
[bullseye] - openssl <not-affected> (Vulnerable code not present)
https://openssl-library.org/news/secadv/20260609.txt

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