Do Son 
TL;DR
OpenSSL published a security advisory on November 10, 2026, covering five vulnerabilities, all rated Low severity. The fixes already sit in the public OpenSSL GitHub repository. However, the OpenSSL security advisory says official releases are “scheduled for 1st December 2026.”
Two bugs hit OpenSSL’s QUIC stack, two affect AES-GCM-SIV encryption, and one causes an infinite loop in CMS encryption. OpenSSL 4.1, 4.0 and 3.5 are affected by all five. Plan to install 4.1.1, 4.0.4 or 3.5.10 when they ship on December 1.
Why It Matters
OpenSSL is a core cryptography library behind TLS and QUIC. Even so, this OpenSSL security advisory describes bugs with limited risk. Most require an unusual setup, such as a QUIC client or a custom IV length. No exploitation or public proof of concept has been reported. Also, none of the five issues affects the OpenSSL FIPS modules.
How the Attack Works
QUIC flaws
CVE-2026-88822 stems from a buffer-length mix-up during automated peer detection. As a result, QUIC may send packets to an address built from uninitialized stack data. This leaks that data to “passive network observers” and breaks the connection.
CVE-2026-95691 is a use-after-free read in the QUIC client. A malicious server can resend a CRYPTO frame to free memory the TLS layer still uses. In turn, this can crash the client or leak one byte of heap data.
AES-GCM-SIV flaws
CVE-2026-88823 treats an empty AAD update as a reset of all earlier AAD. Therefore, “an attacker can forge the AAD of such a message.” Meanwhile, CVE-2026-95692 mishandles IVs of the wrong length. A short IV triggers a heap out-of-bounds read, while a long one is silently truncated.
CMS infinite loop
Finally, CVE-2026-107496 makes CMS_encrypt() loop forever when a recipient EC certificate declares a group order of 1. An attacker must supply that certificate to trigger the hang.
Affected Versions
- OpenSSL 4.1, 4.0 and 3.5: affected by all five flaws
- OpenSSL 3.0, 1.1.1 and 1.0.2: affected only by CVE-2026-107496
- OpenSSL 4.0 and later: CMS bug applies only with enable-ec_explicit_curves
Patch and Mitigation
Upgrade to OpenSSL 4.1.1, 4.0.4 or 3.5.10 once they arrive on December 1. Premium support customers on older branches will get 3.0.24, 1.1.1zk and 1.0.2zt for the CMS bug. Until then, teams can build from the patched GitHub source.
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