Linux Kernel up to 6.18.39/7.1.4 BPF bpf_lru_pop_free deadlock

CVSS Meta Temp Score
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CTI Interest Score
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4.7$0-$5k0.94

Summaryinfo

A vulnerability categorized as problematic has been discovered in Linux Kernel up to 6.18.39/7.1.4. This impacts the function bpf_lru_pop_free of the component BPF. The manipulation results in deadlock. This vulnerability is known as CVE-2026-74337. It is possible to launch the attack remotely. No exploit is available.

Detailsinfo

A vulnerability was found in Linux Kernel up to 6.18.39/7.1.4. It has been classified as problematic. Affected is the function bpf_lru_pop_free of the component BPF. The manipulation with an unknown input leads to a deadlock vulnerability. CWE is classifying the issue as CWE-833. The product contains multiple threads or executable segments that are waiting for each other to release a necessary lock, resulting in deadlock. This is going to have an impact on availability. CVE summarizes:

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix NMI/tracepoint re-entry deadlock on lru locks NMI and tracepoint BPF programs can re-enter the per-CPU or global LRU lock that bpf_lru_pop_free()/push_free() already hold on the same CPU, AA-deadlocking. Lockdep reports "inconsistent {INITIAL USE} -> {IN-NMI}" on &l->lock (syzbot c69a0a2c816716f1e0d5) and "possible recursive locking detected" on &loc_l->lock (syzbot 18b26edb69b2e19f3b33). Prior trylock and rqspinlock based fixes (see links) were nacked because compromised on reliability. This patch converts every LRU lock site to rqspinlock_t and adds a recovery path for some failure windows to avoid node leaks. Failure recovery: - *_pop_free top-level: return NULL; prealloc_lru_pop() already treats that as no-free-element (-ENOMEM). - Cross-CPU steal: skip the victim's locked loc_l, try next CPU. - Post-steal local lock fail: publish stolen node to lockless per-CPU free_llist; next pop on this CPU picks it up. - push_free fail: mark node pending_free=1. __local_list_flush(), __local_list_pop_pending() reclaim the node from pending_list. __bpf_lru_list_shrink_inactive() reclaims the node from inactive list. Nodes from active list are reclaimed by __bpf_lru_list_shrink() or after __bpf_lru_list_rotate_active() demotes it to the inactive.

The advisory is shared for download at git.kernel.org. This vulnerability is traded as CVE-2026-74337 since 08/15/2026. The exploitability is told to be easy. It is possible to launch the attack remotely. The exploitation requires an enhanced level of successful authentication. There are known technical details, but no exploit is available. The MITRE ATT&CK project declares the attack technique as T1499.

Upgrading to version 6.18.40, 7.1.5 or 7.2-rc1 eliminates this vulnerability. Applying the patch 8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5/440a2fdbb40608d55a7b11f2be53592a3785131d/89edbdfc5d0308cef57b71359331de5c4ddbf763 is able to eliminate this problem.

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Productinfo

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Version

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CPE 2.3info

CPE 2.2info

CVSSv4info

VulDB Vector: 🔒
VulDB Reliability: 🔍

CVSSv3info

VulDB Meta Base Score: 4.9
VulDB Meta Temp Score: 4.7

VulDB Base Score: 4.9
VulDB Temp Score: 4.7
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: Deadlock
CWE: CWE-833 / CWE-404
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 6.18.40/7.1.5/7.2-rc1
Patch: 8b0510cc3a4a000d4ed1a56cd96231f3d3ba94c5/440a2fdbb40608d55a7b11f2be53592a3785131d/89edbdfc5d0308cef57b71359331de5c4ddbf763

Timelineinfo

08/15/2026 Advisory disclosed
08/15/2026 +0 days CVE reserved
08/15/2026 +0 days VulDB entry created
08/15/2026 +0 days VulDB entry last update

Sourcesinfo

Vendor: kernel.org

Advisory: git.kernel.org
Status: Confirmed

CVE: CVE-2026-74337 (🔒)
GCVE (CVE): GCVE-0-2026-74337
GCVE (VulDB): GCVE-100-390300

Entryinfo

Created: 08/15/2026 09:40
Changes: 08/15/2026 09:40 (59)
Complete: 🔍
Cache ID: 216::103

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