In the Linux kernel, the following vulnerability has been resolved: bpf: Explicitly check accesses to bpf_sock_addr Syzkaller found a kernel warning on the following sock_addr program: 0: r0 = 0 1: r2 = *(u32 *)(r1 +60) 2: exit which triggers: verifier bug: error during ctx access conversion (0) This is happening because offset 60 in bpf_sock_addr corresponds to an implicit padding of 4 bytes, right after msg_src_ip4. Access to this padding isn't rejected in sock_addr_is_valid_access and it thus later fails to convert the access. This patch fixes it by explicitly checking the various fields of bpf_sock_addr in sock_addr_is_valid_access. I checked the other ctx structures and is_valid_access functions and didn't find any other similar cases. Other cases of (properly handled) padding are covered in new tests in a subsequent patch.

Metrics

No CVSS v4.0

Attack Vector Local

Attack Complexity Low

Privileges Required Low

Scope Unchanged

Confidentiality Impact None

Integrity Impact None

Availability Impact High

User Interaction None

No CVSS v3.0

No CVSS v2

This CVE is not in the KEV list.

Key SSVC decision points have not yet been added.

Affected Vendors & Products

Vendors Products
Linux
  • Linux Kernel

No data.

No data.

References
Link Providers
https://git.kernel.org/stable/c/4f00858cd9bbbdf67159e28b85a8ca9e77c83622 cve-icon cve-icon
https://git.kernel.org/stable/c/6d8b1a21fd5c34622b0c3893c61e4a38d8ba53ec cve-icon cve-icon
https://git.kernel.org/stable/c/6fabca2fc94d33cdf7ec102058983b086293395f cve-icon cve-icon
https://git.kernel.org/stable/c/76e04bbb4296fb6eac084dbfc27e02ccc744db3e cve-icon cve-icon
https://git.kernel.org/stable/c/ad8b4fe5617e3c85fc23267f02500c4f3bf0ff69 cve-icon cve-icon
https://git.kernel.org/stable/c/cdeafacb4f9ff261a96baef519e29480fd7b1019 cve-icon cve-icon
https://git.kernel.org/stable/c/de44cdc50d2dce8718cb57deddf9cf1be9a7759f cve-icon cve-icon
https://git.kernel.org/stable/c/fe9d33f0470350558cb08cecb54cf2267b3a45d2 cve-icon cve-icon
https://lore.kernel.org/linux-cve-announce/2025102820-CVE-2025-40078-258f@gregkh/T cve-icon
https://nvd.nist.gov/vuln/detail/CVE-2025-40078 cve-icon
https://www.cve.org/CVERecord?id=CVE-2025-40078 cve-icon
History

Wed, 29 Oct 2025 13:45:00 +0000

Type Values Removed Values Added
References

Wed, 29 Oct 2025 11:00:00 +0000

Type Values Removed Values Added
First Time appeared Linux
Linux linux Kernel
Vendors & Products Linux
Linux linux Kernel

Wed, 29 Oct 2025 00:15:00 +0000

Type Values Removed Values Added
References
Metrics threat_severity

None

 cvssV3_1

{'score': 5.5, 'vector': 'CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H'}

threat_severity

Moderate

Tue, 28 Oct 2025 12:00:00 +0000

Type Values Removed Values Added
Description In the Linux kernel, the following vulnerability has been resolved: bpf: Explicitly check accesses to bpf_sock_addr Syzkaller found a kernel warning on the following sock_addr program: 0: r0 = 0 1: r2 = *(u32 *)(r1 +60) 2: exit which triggers: verifier bug: error during ctx access conversion (0) This is happening because offset 60 in bpf_sock_addr corresponds to an implicit padding of 4 bytes, right after msg_src_ip4. Access to this padding isn't rejected in sock_addr_is_valid_access and it thus later fails to convert the access. This patch fixes it by explicitly checking the various fields of bpf_sock_addr in sock_addr_is_valid_access. I checked the other ctx structures and is_valid_access functions and didn't find any other similar cases. Other cases of (properly handled) padding are covered in new tests in a subsequent patch.
Title bpf: Explicitly check accesses to bpf_sock_addr
References
cve-icon MITRE

Status: PUBLISHED

Assigner: Linux

Published:

Updated: 2025-10-29T13:19:59.525Z

Reserved: 2025-04-16T07:20:57.160Z

Link: CVE-2025-40078

cve-icon Vulnrichment

No data.

cve-icon NVD

Status : Awaiting Analysis

Published: 2025-10-28T12:15:42.360

Modified: 2025-10-30T15:05:32.197

Link: CVE-2025-40078

cve-icon Redhat

Severity : Moderate

Publid Date: 2025-10-28T00:00:00Z

Links: CVE-2025-40078 - Bugzilla