Bug 2532297 (CVE-2026-89576)

Summary:	CVE-2026-89576 kernel: dm-era: fix shadowed superblock leak on take-snap failure
Product:	[Other] Security Response	Reporter:	OSIDB Bzimport <bzimport>
Component:	vulnerability	Assignee:	Product Security DevOps Team <prodsec-dev>
Status:	NEW ---	QA Contact:
Severity:	low	Docs Contact:
Priority:	low
Version:	unspecified	CC:	akhatavk, aos-team-art-private, asdas, dpaolell, jdelft, jupierce, lgarciaa, mbiarnes, ppalepu, ppostler, prdhamdh, rhel-process-autobot, sghai, sidsharm, suppawar, vlaad, watson-tool-maintainers
Target Milestone:	---	Keywords:	Security
Target Release:	---
Hardware:	All
OS:	Linux
Whiteboard:
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Doc Text:	A flaw was found in the Linux kernel's device-mapper era (dm-era) component. When a snapshot operation fails, a block of metadata is allocated but not properly freed. This leads to a permanent leak of system resources with each failed attempt. Over time, this resource exhaustion can result in a Denial of Service (DoS), causing the system to become unresponsive or crash.	Story Points:	---
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Verified Versions:		Category:	---
oVirt Team:	---	RHEL 7.3 requirements from Atomic Host:
Cloudforms Team:	---	Target Upstream Version:
Embargoed:

Description OSIDB Bzimport 2026-09-11 22:12:21 UTC

In the Linux kernel, the following vulnerability has been resolved:

dm-era: fix shadowed superblock leak on take-snap failure

metadata_take_snap() bumps the live superblock refcount and then
dm_tm_shadow_block() allocates a new block for the metadata snapshot.
If the subsequent dm_sm_inc_block() of writeset_tree_root or
era_array_root fails, the function only unlocks the clone and
returns.  The newly allocated shadow block is never returned to the
metadata space map, so each failed take-snap permanently leaks one
metadata block.

Free the clone with dm_sm_dec_block() on those error paths, matching
the final step of metadata_drop_snap().

Comment 1 Keith Grant 2026-09-18 16:55:16 UTC

Upstream advisory:
https://git.kernel.org/pub/scm/linux/security/vulns.git/plain/cve/published/2026/CVE-2026-89576.mbox