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NVD / CVE Program· CNA Linux

CVE-2025-40348: slab: Avoid race on slab->obj_exts in alloc_slab_obj_exts

Noroxi assessment

Priority: Monitor (action score 0/100)

  • The sources we track (CISA KEV, Exploit-DB, Metasploit, Nuclei, GitHub) show no public exploit code or exploitation in the wild.
  • Probability of exploitation in the next 30 days: 0.19% (FIRST EPSS).
  • Fixed version: Linux Linux 6.12.56, 6.17.6, 6ed8bfd24ce1cb31742b09a3eb557cd008533eec.

Low priority for now. Upgrade to Linux Linux 6.12.56, 6.17.6, 6ed8bfd24ce1cb31742b09a3eb557cd008533eec or later.

Generated automatically from the record's data: CVSS (NVD and CNA), CISA KEV and SSVC, FIRST EPSS, exploit sources, fixed versions. How we calculate it

Primary sources: NVD · CVE.org · FIRST EPSS

In the Linux kernel, the following vulnerability has been resolved: slab: Avoid race on slab->obj_exts in alloc_slab_obj_exts If two competing threads enter alloc_slab_obj_exts() and one of them fails to allocate the object extension vector, it might override the valid slab->obj_exts allocated by the other thread with OBJEXTS_ALLOC_FAIL. This will cause the thread that lost this race and expects a valid pointer to dereference a NULL pointer later on. Update slab->obj_exts atomically using cmpxchg() to avoid slab->obj_exts overrides by racing threads. Thanks for Vlastimil and Suren's help with debugging.

—No exploit Fix available
Published
Dec 16, 2025
Updated
Oct 14, 2026
EPSS
0.1% · 9th percentile
CWE
—

Report tools

JSON

Action score

0

Monitor

Low priority for now.

CVSS
0 / 40 · —
CISA KEV
0 / 30 · Not listed
EPSS
0 / 30 · 0.1%

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Noroxi analysis

What does it mean in your environment?

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Affected systems

Is your version affected?

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—

Versions reported by the vendor

Affected version ranges reported by the assigning authority (Linux). Independent of NVD's CPE analysis and usually ahead of it.

  • Linux Linux

    • 715b6a5b41dae39baeaa40d3386b548bb278b9c2 and later · before c7af5300d78460fc5037ddc77113ba3dbfe77dc0affected · git
    • 07e38a54cabd9b4de7ceb7f075f29ffa463e458a and later · before 7c34feda6a9a203c9744281f1b6671b7dad2012daffected · git
    • f7381b9116407ba2a429977c80ff8df953ea9354 and later · before 6ed8bfd24ce1cb31742b09a3eb557cd008533eecaffected · git
    • 6.12.54 and later · before 6.12.56affected · semver
    • 6.17.4 and later · before 6.17.6affected · semver

Same product

linux: all records

Other highest-scoring records for the same primary product.

  • CVE-2026-74705udp: fix potential use-after-free in tunnel segmentation
    40Plan
  • CVE-2026-74612veth: fix skb length accounting after XDP frag adjustment
    40Plan
  • CVE-2026-74475vxlan: use neigh_ha_snapshot() in route_shortcircuit()
    40Plan

Published before and after this one in the same product

  • ← EarlierCVE-2025-40346Dec 16, 2025 · arch_topology: Fix incorrect error check in topology_parse_cpu_capacity()
    0Monitor
  • ← EarlierCVE-2025-40347Dec 16, 2025 · net: enetc: fix the deadlock of enetc_mdio_lock
    30Monitor
  • Later →CVE-2025-40349Dec 16, 2025 · hfs: validate record offset in hfsplus_bmap_alloc
    31Monitor

Remediation

Which version to upgrade to

Fix versions compiled from the vendor, package registries and Microsoft. Verify the vendor's note before upgrading.

Product / packageFixed versionSource
Linux Linux6.12.56Vendor (CNA)
Linux Linux6.17.6Vendor (CNA)
Linux Linux6ed8bfd24ce1cb31742b09a3eb557cd008533eecVendor (CNA)
Linux Linux7c34feda6a9a203c9744281f1b6671b7dad2012dVendor (CNA)
Linux Linuxc7af5300d78460fc5037ddc77113ba3dbfe77dc0Vendor (CNA)

Exploit status

No known public exploit

No public exploit has been observed yet. That doesn't mean you're safe, only that the bar is a little higher.

Research context

For pentesters and researchers: attack profile, score disagreement, timeline, patch commits, credits, variant and chain candidates, bug bounty scope. All derived from existing data; no exploit code.

Timeline

From publication to today: proof of concept, Metasploit module, CISA KEV and fix record. Dates are as reported by the sources.

No dated events beyond publication.

No history yet (it accumulates with the daily EPSS job).

Patch and commit links

Commit, PR and diff links among the references. A starting point for patch-diffing and variant hunting; fixes, not exploits.

No commit or PR link among the references.

Credits

All researchers

Finders, reporters and analysts named in the CNA record. Click a name for that researcher’s other records.

No credits in the CNA record.

Variant candidates

Same product, same weakness class, within 18 months. If the patch missed the root cause, the sibling bug is here.

No nightly-computed relations.

Chain candidates

An authentication bypass and a privilege-requiring bug in the same product, published close together: combined they may become an unauthenticated path.

—

Bug bounty scope

No known public program.

Source: bounty-targets-data (public HackerOne, Bugcrowd, Intigriti, YesWeHack listings).

Technical details

No CVSS vector for this record, so attack conditions can't be derived.

Weakness class (CWE)

—

Attack context

MITRE CAPEC attack patterns and ATT&CK techniques for this weakness class (CWE). A starting point for detection rules and threat hunting.

MITRE has no CAPEC/ATT&CK mapping for this CWE.

Change log

  1. Fix✗ → ✓

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References

Show all references (2 more)

Vendor advisories and official records. Exploit/PoC links are deliberately left out.

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