Linux: Use After Free
CVE-2022-49416 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 88cc8f963febe192d6ded9df7217f92f380b449a, 4ba81e794f0fad6234f644c2da1ae14d5b95e1c4, 9f1e5cc85ad77e52f54049a94db0407445ae2a34 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 0.34% 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 88cc8f963febe192d6ded9df7217f92f380b449a or 4ba81e794f0fad6234f644c2da1ae14d5b95e1c4 or 9f1e5cc85ad77e52f54049a94db0407445ae2a34 or 265bec4779a38b65e86a25120370f200822dfa76, whichever matches your release line, or a later version.
- Update Linux Kernel to 4.9.318 or 4.14.283 or 4.19.247 or 5.4.198, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, 88cc8f963febe192d6ded9df7217f92f380b449a; 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, 4ba81e794f0fad6234f644c2da1ae14d5b95e1c4; 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, 9f1e5cc85ad77e52f54049a94db0407445ae2a34; 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, 265bec4779a38b65e86a25120370f200822dfa76; 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, 6118bbdf69f4718b02d26bbcf2e497eb66004331; 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, b79110f2bf6022e60e590d2e094728a8eec3e79e; 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, 82c8e7bbdd06c7ed58e22450cc5b37f33a25bb2c; 5bcae31d9cb1ebfad3ad5a3eea04c8cdc329a04f up to, but not including, 4f05a9e15edcdf5b97e0d86ab6ecd5f187289f6c; and 2 more ranges | 88cc8f963febe192d6ded9df7217f92f380b449a, 4ba81e794f0fad6234f644c2da1ae14d5b95e1c4, 9f1e5cc85ad77e52f54049a94db0407445ae2a34, 265bec4779a38b65e86a25120370f200822dfa76, 6118bbdf69f4718b02d26bbcf2e497eb66004331, b79110f2bf6022e60e590d2e094728a8eec3e79e |
| Linux | Linux Kernel | 3.17 up to, but not including, 4.9.318; 4.10 up to, but not including, 4.14.283; 4.15 up to, but not including, 4.19.247; 4.20 up to, but not including, 5.4.198; 5.5 up to, but not including, 5.10.121; 5.11 up to, but not including, 5.15.46; 5.16 up to, but not including, 5.17.14; 5.18 up to, but not including, 5.18.3 | 4.9.318, 4.14.283, 4.19.247, 5.4.198, 5.10.121, 5.15.46 |
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: wifi: mac80211: fix use-after-free in chanctx code In ieee80211_vif_use_reserved_context(), when we have an old context and the new context's replace_state is set to IEEE80211_CHANCTX_REPLACE_NONE, we free the old context in ieee80211_vif_use_reserved_reassign(). Therefore, we cannot check the old_ctx anymore, so we should set it to NULL after this point. However, since the new_ctx replace state is clearly not IEEE80211_CHANCTX_REPLACES_OTHER, we're not going to do anything else in this function and can just return to avoid accessing the freed old_ctx.
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
- git.kernel.org/stable/c/265bec4779a38b65e86a25120370f200822dfa76
- git.kernel.org/stable/c/2965c4cdf7ad9ce0796fac5e57debb9519ea721e
- git.kernel.org/stable/c/4ba81e794f0fad6234f644c2da1ae14d5b95e1c4
- git.kernel.org/stable/c/4f05a9e15edcdf5b97e0d86ab6ecd5f187289f6c
- git.kernel.org/stable/c/6118bbdf69f4718b02d26bbcf2e497eb66004331
- git.kernel.org/stable/c/82c8e7bbdd06c7ed58e22450cc5b37f33a25bb2c
- git.kernel.org/stable/c/88cc8f963febe192d6ded9df7217f92f380b449a
- git.kernel.org/stable/c/9f1e5cc85ad77e52f54049a94db0407445ae2a34
- git.kernel.org/stable/c/b79110f2bf6022e60e590d2e094728a8eec3e79e
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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