Red Hat Enterprise Linux 6: Use After Free
CVE-2023-6270 is a high-severity use after free vulnerability in Red Hat Enterprise Linux 6 from Red Hat, with a CVSS 3.1 base score of 7.0 out of 10. It can be exploited with local access to the system by an attacker with a low-privileged account, without any action from a user. There is no confirmed exploitation so far. EPSS estimates a 0.41% chance of exploitation within 30 days, which is low compared with other CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux Kernel to 6.9 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Red Hat | Red Hat Enterprise Linux 6 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 7 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 8 | Not specified in the record | Not stated |
| Red Hat | Red Hat Enterprise Linux 9 | Not specified in the record | Not stated |
| Debian | Debian Linux | 10.0 | Not stated |
| Linux | Linux Kernel | before 6.9 | 6.9 |
| Fedora Project | Fedora | 39 | Not stated |
Version data comes from the organisation that assigned the CVE. Confirm against the vendor advisory before deciding you are unaffected.
How the severity score breaks down
- Attack vector
- LocalThe attacker needs local access or must trick a user into running something.
- Attack complexity
- HighSuccess depends on conditions outside the attacker's control.
- Privileges required
- LowA basic user account is enough.
- User interaction
- NoneNo action by a victim is required.
- Scope
- UnchangedImpact stays within the vulnerable component.
- Confidentiality
- HighAll data handled by the component can be read.
- Integrity
- HighData or code can be modified at will.
- Availability
- HighThe component can be taken down completely.
Vector: CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.0 | High | CNA (redhat.com) |
| CVSS 3.1 | 7.0 | High | NVD |
Official description
A flaw was found in the ATA over Ethernet (AoE) driver in the Linux kernel. The aoecmd_cfg_pkts() function improperly updates the refcnt on `struct net_device`, and a use-after-free can be triggered by racing between the free on the struct and the access through the `skbtxq` global queue. This could lead to a denial of service condition or potential code execution.
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Use After Free
The product reuses or references memory after it has been freed. At some point afterward, the memory may be allocated again and saved in another pointer, while the original pointer references a location somewhere within the new allocation. Any operations using the original pointer are no longer valid because the memory belongs to the code that operates on the new pointer.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- When freeing pointers, be sure to set them to NULL once they are freed. However, the utilization of multiple or complex data structures may lower the usefulness of this strategy.
Timeline
- CVE record published.
- CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: partial).
- Record last changed materially (score, affected products, status or references).
References
Third-party and government advisories
- access.redhat.com/security/cve/CVE-2023-6270Third Party Advisory
- bugzilla.redhat.com/show_bug.cgi?id=2256786Issue Tracking, Third Party Advisory
- lists.debian.org/debian-lts-announce/2024/06/msg00017.htmlThird Party Advisory
- lists.debian.org/debian-lts-announce/2024/06/msg00020.htmlThird Party Advisory
Other vulnerabilities in Red Hat Enterprise Linux 6
- 7.8 High severity
- 7.5 High severity
- 7.5 High severity
- 7.9 High severity
- 7.6 High severity
- 7.5 High severity
Recent Use After Free vulnerabilities
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.0 High severity
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