CVE-2021-22600
A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny…
High
Known exploited
- Severity
- 7.0 / 10
- High · CVSS 3.1
- Exploit chance (EPSS)
- 6.59%
- Chance of exploitation in the next 30 days. Higher than 93.84% of scored vulnerabilities.
- Known exploited
- Yes
- In CISA's catalog since Apr 11, 2022
- Fix
- None yet
- No fixed version published
Exploited in the wild. Linux Kernel Privilege Escalation Vulnerability (Linux Kernel). Required action: Apply updates per vendor instructions. Due for U.S. federal agencies by May 2, 2022.
Description
A double free bug in packet_set_ring() in net/packet/af_packet.c can be exploited by a local user through crafted syscalls to escalate privileges or deny service. We recommend upgrading kernel past the effected versions or rebuilding past ec6af094ea28f0f2dda1a6a33b14cd57e36a9755
How to fix
No fixed version has been published yet. Until one is, remove or replace the package, or turn off or isolate the affected feature. This page updates when a fix ships.
Severity breakdown
CVSS 3.1 7.0
CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H
- Attack vector
- Local
- Attack complexity
- High
- Privileges required
- Low
- User interaction
- None
- Scope
- Unchanged
- Confidentiality
- High
- Integrity
- High
- Availability
- High
Weakness
CWE-415: Double Free
The product calls free() twice on the same memory address.
How to prevent it
- Architecture and Design: Choose a language that provides automatic memory management.
- Implementation: Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Implementation: Use a static analysis tool to find double free instances.
CWE-415: Double Free
The product calls free() twice on the same memory address.
How to prevent it
- Architecture and Design: Choose a language that provides automatic memory management.
- Implementation: Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Implementation: Use a static analysis tool to find double free instances.
References
Advisories
Fixes and patches
Other links
Timeline
- Published
- Added to CISA's Known Exploited Vulnerabilities catalog
- Remediation due for U.S. federal agencies
- Last updated by the source
- Latest EPSS score
Related advisories
| Advisory | Severity | Why it's related |
|---|---|---|
| GO-2026-4981 Crash when handling long CNAME response in net | High | Same weakness, CWE-415 |
| GHSA-vfvv-c25p-m7mm rkyv: Panic safety bugs in `InlineVec::clear` and `SerVec::clear` enable arbitrary code execution | Medium | Same weakness, CWE-415 |
| CVE-2026-33824 Double free in Windows IKE Extension allows an unauthorized attacker to execute code over a network. | Critical Known exploited | Same weakness, CWE-415 |
| CVE-2025-62215 Concurrent execution using shared resource with improper synchronization ('race condition') in Windows Kernel allows an authorized attacker to elevate… | High Known exploited | Same weakness, CWE-415 |
| GHSA-7mcq-f592-pf7v Slice Ring Buffer and Slice Deque contains four unique double-free vulnerabilities triggered through safe APIs | High | Same weakness, CWE-415 |
| GHSA-pg9f-39pc-qf8g crossbeam-channel Vulnerable to Double Free on Drop | Medium | Same weakness, CWE-415 |
| GHSA-f49c-87jh-g47q TensorFlow has double free in Fractional(Max/Avg)Pool | High | Same weakness, CWE-415 |
| GHSA-v5w6-wcm8-jm4q openssl-src contains Double free after calling `PEM_read_bio_ex` | High | Same weakness, CWE-415 |
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