Linux: Use After Free
CVE-2022-49535 is a high-severity use after free vulnerability in Linux, with a CVSS 3.1 base score of 8.8 out of 10. It can be exploited from the same local network by an unauthenticated attacker, without any action from a user. The record lists versions c7dc74ab7975c9b96284abfe4cca756d75fa4604, 10663ebec0ad5c78493a0dd34c9ee4d73d7ca0df, 577a942df3de2666f6947bdd3a5c9e8d30073424 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 0.35% 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 c7dc74ab7975c9b96284abfe4cca756d75fa4604 or 10663ebec0ad5c78493a0dd34c9ee4d73d7ca0df or 577a942df3de2666f6947bdd3a5c9e8d30073424, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.181 or 5.18.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 52edb2caf675684acf2140a125de4774c691fecd up to, but not including, c7dc74ab7975c9b96284abfe4cca756d75fa4604; 52edb2caf675684acf2140a125de4774c691fecd up to, but not including, 10663ebec0ad5c78493a0dd34c9ee4d73d7ca0df; 52edb2caf675684acf2140a125de4774c691fecd up to, but not including, 577a942df3de2666f6947bdd3a5c9e8d30073424; 5.11 | c7dc74ab7975c9b96284abfe4cca756d75fa4604, 10663ebec0ad5c78493a0dd34c9ee4d73d7ca0df, 577a942df3de2666f6947bdd3a5c9e8d30073424 |
| Linux | Linux Kernel | before 5.15.181; 5.16 up to, but not including, 5.18.3 | 5.15.181, 5.18.3 |
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
- AdjacentThe attacker must be on the same local network segment.
- Attack complexity
- LowNo special conditions are needed; the attack works reliably.
- Privileges required
- NoneNo account or login is needed.
- 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:A/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:H. Scored by CNA.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 8.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: scsi: lpfc: Fix null pointer dereference after failing to issue FLOGI and PLOGI If lpfc_issue_els_flogi() fails and returns non-zero status, the node reference count is decremented to trigger the release of the nodelist structure. However, if there is a prior registration or dev-loss-evt work pending, the node may be released prematurely. When dev-loss-evt completes, the released node is referenced causing a use-after-free null pointer dereference. Similarly, when processing non-zero ELS PLOGI completion status in lpfc_cmpl_els_plogi(), the ndlp flags are checked for a transport registration before triggering node removal. If dev-loss-evt work is pending, the node may be released prematurely and a subsequent call to lpfc_dev_loss_tmo_handler() results in a use after free ndlp dereference. Add test for pending dev-loss before decrementing the node reference count for FLOGI, PLOGI, PRLI, and ADISC handling.
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
Patches and release notes
Recent Use After Free vulnerabilities
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