Linux: Use After Free
CVE-2023-53116 is a high-severity use after free vulnerability in 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 e5d99b29012bbf0e86929403209723b2806500c1, fafcb4b26393870c45462f9af6a48e581dbbcf7e, 04c394208831d5e0d5cfee46722eb0f033cd4083 as the first without the flaw, so updating Linux to one of those releases or later removes the exposure. There is no confirmed exploitation so far. EPSS estimates a 0.55% 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 to e5d99b29012bbf0e86929403209723b2806500c1 or fafcb4b26393870c45462f9af6a48e581dbbcf7e or 04c394208831d5e0d5cfee46722eb0f033cd4083 or a6317235da8aa7cb97529ebc8121cc2a4c4c437a, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.14.311 or 4.19.279 or 5.4.238 or 5.10.176, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, e5d99b29012bbf0e86929403209723b2806500c1; a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, fafcb4b26393870c45462f9af6a48e581dbbcf7e; a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, 04c394208831d5e0d5cfee46722eb0f033cd4083; a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, a6317235da8aa7cb97529ebc8121cc2a4c4c437a; a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, f1d5888a5efe345b63c430b256e95acb0a475642; a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, bcd535f07c58342302a2cd2bdd8894fe0872c8a9; a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, 8ed9813871038b25a934b21ab76b5b7dbf44fc3a; a07b4970f464f13640e28e16dad6cfa33647cc99 up to, but not including, 6173a77b7e9d3e202bdb9897b23f2a8afe7bf286; and 1 more ranges | e5d99b29012bbf0e86929403209723b2806500c1, fafcb4b26393870c45462f9af6a48e581dbbcf7e, 04c394208831d5e0d5cfee46722eb0f033cd4083, a6317235da8aa7cb97529ebc8121cc2a4c4c437a, f1d5888a5efe345b63c430b256e95acb0a475642, bcd535f07c58342302a2cd2bdd8894fe0872c8a9 |
| Linux | Linux Kernel | 4.8 up to, but not including, 4.14.311; 4.15 up to, but not including, 4.19.279; 4.20 up to, but not including, 5.4.238; 5.5 up to, but not including, 5.10.176; 5.11 up to, but not including, 5.15.104; 5.16 up to, but not including, 6.1.21; 6.2 up to, but not including, 6.2.8; 6.3 | 4.14.311, 4.19.279, 5.4.238, 5.10.176, 5.15.104, 6.1.21 |
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 | 9.8 | Critical | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: nvmet: avoid potential UAF in nvmet_req_complete() An nvme target ->queue_response() operation implementation may free the request passed as argument. Such implementation potentially could result in a use after free of the request pointer when percpu_ref_put() is called in nvmet_req_complete(). Avoid such problem by using a local variable to save the sq pointer before calling __nvmet_req_complete(), thus avoiding dereferencing the req pointer after that function call.
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: yes, technical impact: total).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/04c394208831d5e0d5cfee46722eb0f033cd4083
- git.kernel.org/stable/c/6173a77b7e9d3e202bdb9897b23f2a8afe7bf286
- git.kernel.org/stable/c/8ed9813871038b25a934b21ab76b5b7dbf44fc3a
- git.kernel.org/stable/c/a6317235da8aa7cb97529ebc8121cc2a4c4c437a
- git.kernel.org/stable/c/bcd535f07c58342302a2cd2bdd8894fe0872c8a9
- git.kernel.org/stable/c/e5d99b29012bbf0e86929403209723b2806500c1
- git.kernel.org/stable/c/f1d5888a5efe345b63c430b256e95acb0a475642
- git.kernel.org/stable/c/fafcb4b26393870c45462f9af6a48e581dbbcf7e
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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