OpenSSL up to 3.5.9/4.0.3/4.1.0 QUIC getpeername uninitialized variable

Summaryinfo

A vulnerability labeled as critical has been found in OpenSSL up to 3.5.9/4.0.3/4.1.0. This vulnerability affects the function getpeername of the component QUIC. Such manipulation leads to uninitialized variable. This vulnerability is traded as CVE-2026-88822. The attack may be launched remotely. There is no exploit available. The affected component should be upgraded.

Detailsinfo

A vulnerability was found in OpenSSL up to 3.5.9/4.0.3/4.1.0. It has been rated as critical. Affected by this issue is the function getpeername of the component QUIC. The manipulation with an unknown input leads to a uninitialized variable vulnerability. Using CWE to declare the problem leads to CWE-457. The code uses a variable that has not been initialized, leading to unpredictable or unintended results. Impacted is confidentiality, integrity, and availability. CVE summarizes:

Issue summary: QUIC, when performing automated peer detection, may allow uninitialized stack data to leak into the received address which is then used as the destination for outgoing packets. Impact summary: Applications using QUIC's automated peer detection mechanism may receive an invalid address, leading to connection loss and disclosure of uninitialized stack data to an attacker observing the outgoing network traffic. CWE: CWE-457 (Use of Uninitialized Variable) Description: The OpenSSL QUIC stack contains a feature in which, when using an already connected socket, it will auto-detect the peer address during the SSL handshake. This feature uses the getpeername() function, passing a buffer of sufficient length to hold any supported address family, but passes a buffer length that is only sized such that larger addresses, such as IPv6, cannot be retrieved. The getpeername() function however, still returns the full address length, which is accepted as the valid input buffer length, leading to the address buffer containing uninitialized stack data instead of the actual peer address. The invalid peer address is then used as destination for the outgoing packets which leads to a connectivity breakage and a leakage of the uninitialized stack data to passive network observers. FIPS impact: no The FIPS modules in 4.0, 3.6, 3.5, 3.4, and 3.0 are not affected by this CVE as the affected protocol is not implemented in the FIPS module.

The advisory is shared for download at openssl-library.org. This vulnerability is handled as CVE-2026-88822 since 09/10/2026. The exploitation is known to be easy. The attack may be launched remotely. No form of authentication is required for exploitation. There are known technical details, but no exploit is available. The current price for an exploit might be approx. USD $5k-$25k (estimation calculated on 11/11/2026).

Upgrading to version 3.5.10, 4.0.4 or 4.1.1 eliminates this vulnerability.

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Productinfo

Type

• Network Encryption Software

Name

• OpenSSL

Version

• 3.5.0
• 3.5.1
• 3.5.2
• 3.5.3
• 3.5.4
• 3.5.5
• 3.5.6
• 3.5.7
• 3.5.8
• 3.5.9
• 4.0
• 4.0.0
• 4.0.1
• 4.0.2
• 4.0.3
• 4.1.0

License

• open-source

Website

• Product: https://www.openssl.org/

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