Detections
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Chainguard: multiple openssl-4.0 packages: security update to 4.0.3-r0

high Tenable Cloud Security Plugin ID 477682

Description

There are packages installed that are affected by a vulnerability referenced in the following CVE:

 - Issue summary: The first concurrent use of the same X.509 certificate by several threads may cause its
 cached extension data to be freed while another thread is still using it. Impact summary: A remote,
 unauthenticated peer could crash a multi-threaded TLS client, or a multi-threaded TLS server that requests
 client certificates, if the first certificate chains built to the same trusted CA certificate are built by
 several connections at the same time. This is a use-after-free read, which is likely to crash the process,
 resulting in a Denial of Service. CWE: CWE-416: Use After Free Description: OpenSSL caches the decoded
 values of a certificate's X.509v3 extensions inside the X509 object the first time they are needed. In
 OpenSSL 4.0 this cache is built in two phases: the extension values are computed while holding a read lock
 on the certificate, and the results are then installed into the certificate under a write lock. Because a
 read lock does not exclude other readers, several threads can compute the cache for the same certificate
 at the same time. Each thread that subsequently acquires the write lock installs its own results and frees
 the values installed by the thread before it, even though that earlier thread has already marked the cache
 as complete and may have returned pointers into it to its caller. A caller still using those pointers then
 reads freed memory. Any certificate shared between threads is exposed the first time its extensions are
 decoded. In TLS the certificates at risk are the trusted CA certificates supplied for chain verification,
 by whatever means, since these are shared by every connection and their extensions are decoded and cached
 the first time a chain is built to them. Certificates sent by the peer are decoded separately for each
 connection and are not shared, so they are not affected. In a TLS client verifying server certificates, or
 a TLS server that requests and verifies client certificates, the use-after-free could only occur if the
 first chains built to the same trusted CA are built by several connections at the same time. FIPS impact:
 no The FIPS module is not affected as X.509 certificate handling is outside of the OpenSSL FIPS module
 boundary. OpenSSL 4.0 is vulnerable to this issue. OpenSSL 3.6, 3.5, 3.4, 3.0, 1.1.1 and 1.0.2 are not
 affected by this issue. OpenSSL 4.0 users should upgrade to OpenSSL 4.0.3. This issue was reported on 27
 August 2026 by Tim Becker (Xint.io) and independently in a public report on 31 August 2026 by aydinmercan.
 The fix has been developed by Bob Beck. -- cut (non-publishing metadata for internal use) -- Reported by:
 Tim Becker (Xint.io), aydinmercan Fixed by: Bob Beck (CVE-2026-84783)

Solution

Update the openssl-4.0 library and its related packages to version 4.0.3-r0 or later.

Plugin Details

Severity: High

ID: 477682

Version: Revision 1.1

Type: Local

Published: 10/28/2026

Updated: 10/28/2026

Risk Information

VPR

Risk Factor: Low

Score: 3

Percentile: 23.64

CVSS v2

Risk Factor: High

Base Score: 7.8

Temporal Score: 5.8

Vector: CVSS2#AV:N/AC:L/Au:N/C:N/I:N/A:C

CVSS Score Source: CVE-2026-84783

CVSS v3

Risk Factor: High

Base Score: 7.5

Temporal Score: 6.5

Vector: CVSS:3.0/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H

Temporal Vector: CVSS:3.0/E:U/RL:O/RC:C

Vulnerability Information

Exploit Ease: No known exploits are available

Vulnerability Publication Date: 9/29/2026

Reference Information

CVE: CVE-2026-84783