Linux Kernel up to 6.12.100/6.18.41/7.1.5/7.2-rc4 btrfs btrfs_drop_extent_map_range use after free

CVSS Meta Temp Score
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Current Exploit Price (≈)
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CTI Interest Score
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9.5$5k-$25k1.57+

Summaryinfo

A vulnerability has been found in Linux Kernel up to 6.12.100/6.18.41/7.1.5/7.2-rc4 and classified as very critical. Affected by this issue is the function btrfs_drop_extent_map_range of the component btrfs. The manipulation leads to use after free. This vulnerability is referenced as CVE-2026-68442. Remote exploitation of the attack is possible. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.12.100/6.18.41/7.1.5/7.2-rc4 and classified as very critical. This issue affects the function btrfs_drop_extent_map_range of the component btrfs. The manipulation with an unknown input leads to a use after free vulnerability. Using CWE to declare the problem leads to CWE-416. Referencing memory after it has been freed can cause a program to crash, use unexpected values, or execute code. Impacted is confidentiality, integrity, and availability. The summary by CVE is:

In the Linux kernel, the following vulnerability has been resolved: btrfs: don't propagate EXTENT_FLAG_LOGGING to split extent maps When btrfs_drop_extent_map_range() splits an extent map, the new split maps inherit the original map's flags through a local 'flags' variable. Commit f86f7a75e2fb ("btrfs: use the flags of an extent map to identify the compression type") changed the EXTENT_FLAG_LOGGING clearing to operate on em->flags instead of that local 'flags' copy, so a split of an extent map that is currently being logged wrongly inherits EXTENT_FLAG_LOGGING. The flag is then never cleared on the split, and when it is freed while still on the inode's modified_extents list (for example by the extent map shrinker) it trips the WARN_ON(!list_empty(&em->list)) in btrfs_free_extent_map() and leads to a use-after-free. Clear EXTENT_FLAG_LOGGING from the local 'flags' copy used for the splits and only clear EXTENT_FLAG_PINNED from em->flags, restoring the behaviour prior to f86f7a75e2fb.

It is possible to read the advisory at git.kernel.org. The identification of this vulnerability is CVE-2026-68442 since 07/30/2026. The exploitation is known to be easy. The attack may be initiated remotely. Technical details of the vulnerability are known, but there is no available exploit. The pricing for an exploit might be around USD $5k-$25k at the moment (estimation calculated on 08/12/2026).

Upgrading to version 6.12.101, 6.18.42, 7.1.6 or 7.2-rc5 eliminates this vulnerability. Applying the patch 2a9246a424f45f33a1b8367052611ebe874868ad/9304713b70e7e1450e3a76e758836fe5391bfa95/0e465c63f103a5ce6849614d6bda048d70eebec8/5eff4d5b17fa1950e80bfd1ba43dc0699e61a644 is able to eliminate this problem.

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Productinfo

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 9.9
VulDB Meta Temp Score: 9.5

VulDB Base Score: 9.9
VulDB Temp Score: 9.5
VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv2info

AVACAuCIA
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💳💳💳💳💳💳
💳💳💳💳💳💳
VectorComplexityAuthenticationConfidentialityIntegrityAvailability
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VulDB Base Score: 🔒
VulDB Temp Score: 🔒
VulDB Reliability: 🔍

Exploitinginfo

Class: Use after free
CWE: CWE-416 / CWE-119
CAPEC: 🔒
ATT&CK: 🔒

Physical: No
Local: No
Remote: Yes

Availability: 🔒
Status: Not defined
Price Prediction: 🔍
Current Price Estimation: 🔒

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Threat Intelligenceinfo

Interest: 🔍
Active Actors: 🔍
Active APT Groups: 🔍

Countermeasuresinfo

Recommended: Upgrade
Status: 🔍

0-Day Time: 🔒

Upgrade: Kernel 6.12.101/6.18.42/7.1.6/7.2-rc5
Patch: 2a9246a424f45f33a1b8367052611ebe874868ad/9304713b70e7e1450e3a76e758836fe5391bfa95/0e465c63f103a5ce6849614d6bda048d70eebec8/5eff4d5b17fa1950e80bfd1ba43dc0699e61a644

Timelineinfo

07/30/2026 CVE reserved
08/12/2026 +13 days Advisory disclosed
08/12/2026 +0 days VulDB entry created
08/12/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-68442 (🔒)
GCVE (CVE): GCVE-0-2026-68442
GCVE (VulDB): GCVE-100-388895

Entryinfo

Created: 08/12/2026 02:34
Changes: 08/12/2026 02:34 (59)
Complete: 🔍
Cache ID: 216::103

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