Bug 2565677 (CVE-2026-121995)

Summary:	CVE-2026-121995 gdb: gdb: stack buffer overflow in parse_tracepoint_definition via stale rs->buf tail
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 in the GDB client's tracepoint upload handler allows an attacker-controlled debug stub to corrupt stack memory automatically during connection setup. The overflow results from GDB reading beyond the current reply boundary into a stale prior reply in the shared packet buffer.	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 2026-11-03 10:03:08 UTC

Stack buffer overflow in parse_tracepoint_definition (gdb/tracepoint.c), Z branch. The packet buffer rs->buf is reused between requests without clearing. When a short qTsP reply follows a longer qTfP reply, the parser's p pointer — advanced through strchr/unpack_varlen_hex calls — walks past the short reply's NUL terminator into stale data from the prior longer reply. hex2bin then copies strlen(p)/2 pairs into an alloca buffer sized only for the short reply, overflowing it. Fires automatically during target remote connection setup with no additional user commands.