Kernel heap disclosure via unchecked netlink attribute
Published Jul 25, 2023 · Updated Nov 14, 2025
Out-of-bounds read in Red Hat Enterprise Linux 9 XFRM allows local users to disclose kernel heap data via malformed netlink attributes. The xfrma_policy table omits the NLA_U32 rule for XFRMA_MTIMER_THRESH, so xfrm_update_ae_params reads four bytes from an empty attribute and later returns them to userspace. Exploitation requires CAP_NET_ADMIN and exposes four bytes of sprayed kernel heap data without reported integrity or availability impact.
Summary
What happened
Out-of-bounds read in Red Hat Enterprise Linux 9 XFRM allows local users to disclose kernel heap data via malformed netlink attributes. The xfrma_policy table omits the NLA_U32 rule for XFRMA_MTIMER_THRESH, so xfrm_update_ae_params reads four bytes from an empty attribute and later returns them to userspace. Exploitation requires CAP_NET_ADMIN and exposes four bytes of sprayed kernel heap data without reported integrity or availability impact.
The record
- CVE
- CVE-2023-3773
- Published
- Jul 25, 2023
- Updated
- Nov 14, 2025
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 9
- Classifications
- CWE-125
- Attack vector
- local
- Privileges
- admin
Timeline
How it unfolded
- Jul 25, 2023CVE publishedPublication date reported by the CVE source.
- Nov 14, 2025Record updatedLatest update available in the CVE record.
Exploitability
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What conditions does exploitation require?
What is affected?
Attacks
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Weakness, pattern, technique
Public exploit references
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Technologies
Your stack
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Your stack
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