CVE-2026-95691

EUVD-2026-121636
Issue summary: A retransmitted QUIC CRYPTO frame can release packet storage
while the TLS record layer retains a direct pointer into that storage causing
use after free.

Impact summary: A malicious QUIC server can cause a heap-use-after-free read
in the OpenSSL QUIC client. The server can also identify one allocator-adjacent
byte through the client's protected Handshake response.

CWE: CWE-416: Use After Free

Description: During CRYPTO stream processing, a pointer into the first frame's
memory on the stream is lent to the TLS handshake processing. The memory
must remain stable until it is processed and released. However the processing
of retransmitted CRYPTO frames could release the memory if the retransmitted
frame fully overlapped the existing frame. This then causes use-after-free read
when the TLS handshake processing continues.

The use-after-free read can lead to a Denial-of-Service of the client
application or a minor leak of information about the heap memory contents
that might be overwritten with other data, subsequently allocated by
the application, to the peer.

FIPS impact: no
The FIPS module is not affected as the QUIC implementation is outside of
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 (CNA/ADP records, vendor advisories, Enginsight analysis).
VendorProductVersionSource
opensslopenssl
4.1.0 ≤
𝑥
< 4.1.1
CNA
opensslopenssl
4.0.0 ≤
𝑥
< 4.0.4
CNA
opensslopenssl
3.5.0 ≤
𝑥
< 3.5.10
CNA
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Debian Releases
Debian Product
Codename
openssl
bookworm
vulnerable
bookworm (security)
vulnerable
forky
vulnerable
sid
vulnerable
trixie
vulnerable
trixie (security)
vulnerable