[From nobody Tue Aug 25 21:31:08 2026
Received: (at submit) by bugs.debian.org; 7 Aug 2026 06:38:50 +0000
X-Spam-Checker-Version: SpamAssassin 4.0.1-bugs.debian.org_2005_01_02
 (2024-03-25) on buxtehude.debian.org
X-Spam-Level: 
X-Spam-Status: No, score=-9.9 required=4.0 tests=BAYES_00, FOURLA,
 FROMDEVELOPER, 
 NO_RELAYS,XMAILER_REPORTBUG autolearn=ham autolearn_force=no
 version=4.0.1-bugs.debian.org_2005_01_02
X-Spam-Bayes: score:0.0000 Tokens: new, 25; hammy, 149; neutral, 108; spammy,
 1. spammytokens:0.987-1--singleresponse
 hammytokens:0.000-+--XDebbugsCc, 0.000-+--X-Debbugs-Cc,
 0.000-+--H*F:U*carnil, 0.000-+--H*Ad:N*Bug, 0.000-+--HTo:N*Debian
Return-path: &lt;carnil@debian.org&gt;
Received: via submission by buxtehude.debian.org with esmtp (Exim 4.96)
 (envelope-from &lt;carnil@debian.org&gt;) id 1wsEEC-005kkQ-1w
 for submit@bugs.debian.org; Fri, 07 Aug 2026 06:38:50 +0000
Content-Type: text/plain; charset=&quot;us-ascii&quot;
MIME-Version: 1.0
Content-Transfer-Encoding: 7bit
From: Salvatore Bonaccorso &lt;carnil@debian.org&gt;
To: Debian Bug Tracking System &lt;submit@bugs.debian.org&gt;
Subject: openssl: CVE-2026-54876
Message-ID: &lt;178608472656.959141.10315207682838326053.reportbug@eldamar.lan&gt;
X-Mailer: reportbug 13.2.0+nmu1
Date: Fri, 07 Aug 2026 08:38:46 +0200
Delivered-To: submit@bugs.debian.org

Source: openssl
Version: 3.6.3-1
Severity: important
Tags: security upstream
X-Debbugs-Cc: carnil@debian.org, Debian Security Team &lt;team@security.debian.org&gt;

Hi,

The following vulnerability was published for openssl.

CVE-2026-54876[0]:
| Issue summary: A malicious TLS server can cause a memory leak in a
| TLS client that has enabled OCSP response checking by sending an
| OCSP response that contains no single response entries.  Impact
| summary: An attacker can leak an attacker-tunable amount of memory
| per TLS handshake in a victim client application. A long-running
| client that repeatedly connects to a malicious server can have its
| memory exhausted, resulting in a Denial of Service.  CWE: CWE-401:
| Missing Release of Memory after Effective Lifetime  Description: The
| affected function is called during X.509 certificate chain
| verification when OCSP response checking is enabled with the
| X509_V_FLAG_OCSP_RESP_CHECK or X509_V_FLAG_OCSP_RESP_CHECK_ALL
| verification flags, for example when a TLS client verifies an OCSP
| response stapled into the TLS handshake by the server.  When the
| received BasicOCSPResponse contains an empty SEQUENCE OF
| SingleResponse, which is permitted on the wire and accepted by the
| OpenSSL decoder, the OCSP_BASICRESP structure allocated by
| OCSP_response_get1_basic() was not freed because an early return
| bypassed the cleanup code at the end of the function.  The amount of
| memory leaked per handshake can be amplified by the attacker by
| padding the certs field of the BasicOCSPResponse with bogus
| certificates, which are parsed and stored in the leaked structure
| before the empty response check triggers the early return. A long-
| running TLS client that repeatedly connects to a malicious server
| can have its memory exhausted over time.  OCSP response checking is
| not enabled by default. Only client applications that explicitly
| enable the OCSP response check verification flags are affected.
| FIPS impact: no  The FIPS modules in 4.0 and 3.6 are not affected by
| this issue as the affected code is outside the OpenSSL FIPS module
| boundary.


If you fix the vulnerability please also make sure to include the
CVE (Common Vulnerabilities &amp; Exposures) id in your changelog entry.

For further information see:

[0] https://security-tracker.debian.org/tracker/CVE-2026-54876
    https://www.cve.org/CVERecord?id=CVE-2026-54876
[1] https://openssl-library.org/news/secadv/20260805.txt

Please adjust the affected versions in the BTS as needed.

Regards,
Salvatore
]