Bug 2497344 (CVE-2026-59692)

Summary:	CVE-2026-59692 gstreamer1-plugins-bad-free: gstreamer: DTLS certificate Subject DN stack buffer overflow in openssl_verify_callback
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security <prodsec-ir-bot>
Status:	NEW ---	QA Contact:
Severity:	high	Docs Contact:
Priority:	high
Version:	unspecified	CC:	rhel-process-autobot, security-response-team, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
Fixed In Version:		Doc Type:	---
Doc Text:	A stack buffer overflow vulnerability was found in GStreamer's DTLS plugin. During a DTLS handshake, the peer certificate Subject Distinguished Name is printed into a fixed-size 2048-byte stack buffer without bounds checking. A remote unauthenticated attacker can send a certificate with an oversized Subject DN that exceeds the buffer, causing a stack buffer overflow and process crash, resulting in denial of service.	Story Points:	---
Clone Of:		Environment:
Last Closed:		Type:	---
Regression:	---	Mount Type:	---
Documentation:	---	CRM:
Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-07-06 13:42:59 UTC

A stack buffer overflow was found in GStreamer's DTLS plugin (gst-plugins-bad). In openssl_verify_callback(), the peer certificate Subject DN is printed using X509_NAME_print_ex() into a memory BIO, then read via BIO_read() into a fixed gchar buf[2048] on the stack. The number of bytes read comes directly from the X509_NAME_print_ex() return value without bounds checking against the buffer size.

A remote DTLS peer can send a certificate with an oversized Subject DN (many long OU fields) so that the formatted output exceeds 2048 bytes, causing a stack buffer overflow during the DTLS handshake.

File: subprojects/gst-plugins-bad/ext/dtls/gstdtlsconnection.c
Function: openssl_verify_callback() (lines 1136-1144)

Exploitability analysis:
- The overflow content is TEXT ONLY (X509_NAME_print_ex with XN_FLAG_MULTILINE escapes all binary/control characters to printable ASCII sequences like \XX)
- Stack canary (-fstack-protector-strong) terminates the process before return address corruption is exploitable
- Arbitrary byte injection is impossible: null bytes become \00 (3 printable chars), high-bit bytes become \XX
- RCE is NOT achievable. Maximum impact is denial of service (crash)

Attack vector: Unauthenticated remote DTLS-SRTP/WebRTC peer triggers this during handshake by presenting a crafted certificate. No user interaction required.

Affected: GStreamer gst-plugins-bad (reproduced on 1.28.3)
Fixed: Planned for GStreamer 1.28.5
Fix MR: https://gitlab.freedesktop.org/gstreamer/gstreamer-security/-/merge_requests/99
Upstream issue: https://gitlab.freedesktop.org/gstreamer/gstreamer/-/work_items/5172 (confidential)
Advisory: GST-SA-2026-0062

Reporter: Clouditera Security; Z.ai Security; NSFOCUS
PSIRT Ticket: PSIRTSUPT-19090

Comment 1 errata-xmlrpc 2026-07-28 19:43:47 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10

Via RHSA-2026:47180 https://access.redhat.com/errata/RHSA-2026:47180

Comment 2 errata-xmlrpc 2026-07-29 02:02:08 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9

Via RHSA-2026:47179 https://access.redhat.com/errata/RHSA-2026:47179

Comment 3 errata-xmlrpc 2026-07-29 07:20:45 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8

Via RHSA-2026:47731 https://access.redhat.com/errata/RHSA-2026:47731

Comment 4 errata-xmlrpc 2026-08-13 16:39:15 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 10.0 Extended Update Support

Via RHSA-2026:54659 https://access.redhat.com/errata/RHSA-2026:54659

Comment 5 errata-xmlrpc 2026-08-13 18:04:36 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.6 Extended Update Support

Via RHSA-2026:54660 https://access.redhat.com/errata/RHSA-2026:54660

Comment 6 errata-xmlrpc 2026-08-13 18:08:32 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.4 Update Services for SAP Solutions

Via RHSA-2026:54658 https://access.redhat.com/errata/RHSA-2026:54658

Comment 7 errata-xmlrpc 2026-08-13 18:11:22 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.6 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.6 Extended Update Support Long-Life Add-On

Via RHSA-2026:54665 https://access.redhat.com/errata/RHSA-2026:54665

Comment 8 errata-xmlrpc 2026-08-13 18:17:11 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.8 Update Services for SAP Solutions
  Red Hat Enterprise Linux 8.8 Telecommunications Update Service

Via RHSA-2026:54664 https://access.redhat.com/errata/RHSA-2026:54664

Comment 9 errata-xmlrpc 2026-08-14 00:07:11 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 7 Extended Lifecycle Support

Via RHSA-2026:54752 https://access.redhat.com/errata/RHSA-2026:54752

Comment 10 errata-xmlrpc 2026-08-19 03:48:19 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 9.2 Update Services for SAP Solutions

Via RHSA-2026:56658 https://access.redhat.com/errata/RHSA-2026:56658

Comment 11 errata-xmlrpc 2026-08-19 05:28:08 UTC

This issue has been addressed in the following products:

  Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
  Red Hat Enterprise Linux 8.4 Extended Update Support Long-Life Add-On

Via RHSA-2026:56772 https://access.redhat.com/errata/RHSA-2026:56772