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Review reviewHigh

CVE-2024-40909

Linux Linux, linux kernel

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a potential use-after-free in bpf_link_free() After commit 1a80dbcb2dba, bpf_link can be freed by link->ops->dealloc_deferred, but the code still tests and uses link->ops->dealloc afterward, which leads to a use-after-free as reported by syzbot. Actually, one of them should be sufficient, so just call one of them instead of both. Also add a WARN_ON() in case of any problematic implementation.

CVSS
7.8
EPSS
0.28%
19.9% percentile
CISA KEV
Not listed
Published
2024.07.12
PRIORITY ASSESSMENT

Review review

The CVSS severity warrants an early asset and exposure review.

Known exploitationNot established by KEV
Exploit probability0.28%
Technical severityCVSS 7.8

Vulnerability overview

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix a potential use-after-free in bpf_link_free() After commit 1a80dbcb2dba, bpf_link can be freed by link->ops->dealloc_deferred, but the code still tests and uses link->ops->dealloc afterward, which leads to a use-after-free as reported by syzbot. Actually, one of them should be sufficient, so just call one of them instead of both. Also add a WARN_ON() in case of any problematic implementation.

Affected product and versions

Product
Linux Linux, linux kernel
Affected versions
>= 876941f533e7b47fc69977fc4551c02f2d18af97 < 91cff53136daeff50816b0baeafd38a6976f6209, >= 1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce < fa97b8fed9896f1e89cb657513e483a152d4c382, >= 1a80dbcb2dbaf6e4c216e62e30fa7d3daa8001ce < 2884dc7d08d98a89d8d65121524bb7533183a63a, >= 5d8d447777564b35f67000e7838e7ccb64d525c8, >= 6.6.26 < 6.6.35, >= 6.8.5 < 6.9, >= 6.9, >= 6.9 < 6.9.6, 6.10
Fixed versions
6.6.35, 6.9.6

Recommended response sequence

Confirm exposure before applying a vendor-supported change.

Full remediation guide
  1. 1
    Identify

    Confirm that Linux Linux, linux kernel and an affected version are present.

  2. 2
    Prioritize

    Combine exploitation signals with asset exposure and business criticality.

  3. 3
    Remediate

    Follow the vendor advisory or supported update path and preserve rollback options.

  4. 4
    Verify

    Recheck the version, service health, access paths, and relevant logs.

Technical data

CVSS vector
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
CWE
CWE-416
CVE-2024-40909 — Linux Linux, linux kernel | SECUFOCUS NOW