Heap disclosure and crash via swapped reply length
Published Apr 4, 2024 · Updated Nov 20, 2025
Heap buffer over-read in X.Org Server before 21.1.12 allows local users to disclose heap data and crash the server through an X client. ProcXIGetSelectedEvents uses a byte-swapped reply length as the byte count, so a small 32-bit value can drive a large out-of-bounds heap read returned to the client. Access to the X server and a client with different endianness are required; the read ends at an unmapped page, causing a segmentation fault.
Summary
What happened
Heap buffer over-read in X.Org Server before 21.1.12 allows local users to disclose heap data and crash the server through an X client. ProcXIGetSelectedEvents uses a byte-swapped reply length as the byte count, so a small 32-bit value can drive a large out-of-bounds heap read returned to the client. Access to the X server and a client with different endianness are required; the read ends at an unmapped page, causing a segmentation fault.
The record
- CVE
- CVE-2024-31080
- Published
- Apr 4, 2024
- Updated
- Nov 20, 2025
- Vendor
- Red Hat
- Product
- Red Hat Enterprise Linux 8.4 Advanced Mission Critical Update Support
- Classifications
- CWE-126, T1005, T1499
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Apr 4, 2024CVE publishedPublication date reported by the CVE source.
- Nov 20, 2025Record updatedLatest update available in the CVE record.
Exploitability
Present is not the same as exploitable
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Is a vulnerable build present?
Affected versions are unavailable in this record. Check the vendor advisory for version and patch details.
What conditions does exploitation require?
What is affected?
Published CVSS scores
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Attacks
What attackers are doing with it
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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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