Local privilege escalation via unsigned length underflow
Published Feb 11, 2022 · Updated Oct 21, 2025
Heap-based buffer overflow in Linux kernel packages in Red Hat Enterprise Linux 8.4 and later allows local users to gain root privileges. legacy_parse_param checks len against an unsigned PAGE_SIZE - 2 - size expression; an oversized accumulated option length underflows the subtraction and permits a write past the heap buffer. Unprivileged access requires enabled unprivileged user namespaces and a filesystem that falls back to legacy parameter handling; otherwise namespaced CAP_SYS_ADMIN is required.
Summary
What happened
Heap-based buffer overflow in Linux kernel packages in Red Hat Enterprise Linux 8.4 and later allows local users to gain root privileges. legacy_parse_param checks len against an unsigned PAGE_SIZE - 2 - size expression; an oversized accumulated option length underflows the subtraction and permits a write past the heap buffer. Unprivileged access requires enabled unprivileged user namespaces and a filesystem that falls back to legacy parameter handling; otherwise namespaced CAP_SYS_ADMIN is required.
The record
- CVE
- CVE-2022-0185
- Published
- Feb 11, 2022
- Updated
- Oct 21, 2025
- Vendor
- The Linux Kernel Organization
- Product
- Linux Kernel
- Classifications
- CWE-190, CWE-191, T1068
- Attack vector
- local
- Privileges
- authenticated
Timeline
How it unfolded
- Feb 11, 2022CVE publishedPublication date reported by the CVE source.
- Aug 21, 2024Exploitation reportedCISA Known Exploited Vulnerabilities Catalog entry
- Oct 21, 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?
Compare these published version ranges with your installed build and any vendor patches.
- Affected versionversion=8.4
What conditions does exploitation require?
What is affected?
Published CVSS scores
CVSS describes severity. EPSS estimates exploitation probability.
Attacks
What attackers are doing with it
Daily unique IPs observed by Shadowserver honeypots for known exploited vulnerabilities (KEVs). Missing observations do not establish an absence of attacks.
Weakness, pattern, technique
Public exploit references
- Crusaders of Rust demonstration exploitsfunctional · demonstrated
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Reported exploitation
- CISA Known Exploited Vulnerabilities Catalog entryknown exploited catalog
Technologies
Your stack
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Your stack
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