Kernel: Use After Free
CVE-2023-3609 is a high-severity use after free vulnerability in Kernel from Linux, with a CVSS 3.1 base score of 7.8 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. The record lists versions 4.14.322, 4.19.291, 5.4.248 as the first without the flaw, so updating Kernel to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.49% 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 Kernel to 4.14.322 or 4.19.291 or 5.4.248 or 5.10.185, whichever matches your release line, or a later version.
- Update SIMATIC S7-1500 CPU 1518-4 PN/DP MFP to V3.1.5 or a later version.
- Update SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP to V3.1.5 or a later version.
- Read the advisory on git.kernel.org for workarounds and exact fixed builds.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Kernel | 4.14.0 up to, but not including, 4.14.322; 4.15.0 up to, but not including, 4.19.291; 4.20.0 up to, but not including, 5.4.248; 5.5.0 up to, but not including, 5.10.185; 5.11.0 up to, but not including, 5.15.118; 5.16.0 up to, but not including, 6.1.35; 6.2.0 up to, but not including, 6.3.9 | 4.14.322, 4.19.291, 5.4.248, 5.10.185, 5.15.118, 6.1.35 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Siemens | SIMATIC S7-1500 TM MFP - GNU/Linux subsystem | before V1.1 | V1.1 |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP | V3.1.0 up to, but not including, V3.1.5 | V3.1.5 |
| Linux | Linux Kernel | 4.14 up to, but not including, 4.14.322; 4.15 up to, but not including, 4.19.291; 4.20 up to, but not including, 5.4.248; 5.5 up to, but not including, 5.10.185; 5.11 up to, but not including, 5.15.118; 5.16 up to, but not including, 6.1.35; 6.2 up to, but not including, 6.3.9; 6.4 | 4.14.322, 4.19.291, 5.4.248, 5.10.185, 5.15.118, 6.1.35 |
| Debian | Debian Linux | 10.0; 11.0 | 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
- LowNo special conditions are needed; the attack works reliably.
- 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:L/PR:L/UI:N/S:U/C:H/I:H/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA (google.com) |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
A use-after-free vulnerability in the Linux kernel's net/sched: cls_u32 component can be exploited to achieve local privilege escalation. If tcf_change_indev() fails, u32_set_parms() will immediately return an error after incrementing or decrementing the reference counter in tcf_bind_filter(). If an attacker can control the reference counter and set it to zero, they can cause the reference to be freed, leading to a use-after-free vulnerability. We recommend upgrading past commit 04c55383fa5689357bcdd2c8036725a55ed632bc.
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: total).
- Record last changed materially (score, affected products, status or references).
References
Advisories
Third-party and government advisories
- packetstormsecurity.com/files/175072/Kernel-Live-Patch-Security-Notice-LSN-0098-1.htmlThird Party Advisory, VDB Entry
- packetstormsecurity.com/files/175963/Kernel-Live-Patch-Security-Notice-LSN-0099-1.htmlThird Party Advisory
- lists.debian.org/debian-lts-announce/2023/10/msg00027.htmlMailing List, Third Party Advisory
- security.netapp.com/advisory/ntap-20230818-0005/Third Party Advisory
- debian.org/security/2023/dsa-5480Third Party Advisory
Other references
Other vulnerabilities in Kernel
- 7.1 High severity
- 7.8 High severity
Linux Kernel Use-After-Free Exploited
- 7.8 High severity
- 7.1 High severity
- 7.4 High severity
- 7.0 High severity
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
- 8.8 High severity
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