Linux: Out-of-bounds Read
CVE-2022-50255 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 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 d9c79fbcbdb6cb10c07c85040eaf615180b26c48, 149198d0b884e4606ed1d29b330c70016d878276, f8bae1853196b52ede50950387f5b48cf83b9815 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 0.17% 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 d9c79fbcbdb6cb10c07c85040eaf615180b26c48 or 149198d0b884e4606ed1d29b330c70016d878276 or f8bae1853196b52ede50950387f5b48cf83b9815 or 0934ae9977c27133449b6dd8c6213970e7eece38, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.75 or 5.19.17 or 6.0.3, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | bd82631d7ccdc894af2738e47abcba2cb6e7dea9 up to, but not including, d9c79fbcbdb6cb10c07c85040eaf615180b26c48; bd82631d7ccdc894af2738e47abcba2cb6e7dea9 up to, but not including, 149198d0b884e4606ed1d29b330c70016d878276; bd82631d7ccdc894af2738e47abcba2cb6e7dea9 up to, but not including, f8bae1853196b52ede50950387f5b48cf83b9815; bd82631d7ccdc894af2738e47abcba2cb6e7dea9 up to, but not including, 0934ae9977c27133449b6dd8c6213970e7eece38; 5.10 | d9c79fbcbdb6cb10c07c85040eaf615180b26c48, 149198d0b884e4606ed1d29b330c70016d878276, f8bae1853196b52ede50950387f5b48cf83b9815, 0934ae9977c27133449b6dd8c6213970e7eece38 |
| Linux | Linux Kernel | 5.10 up to, but not including, 5.15.75; 5.16 up to, but not including, 5.19.17; 6.0 up to, but not including, 6.0.3 | 5.15.75, 5.19.17, 6.0.3 |
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
- 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
- NoneNothing can be modified.
- 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:N/A:H. Scored by NVD.
| Scoring system | Score | Severity | Scored by |
|---|---|---|---|
| CVSS 3.1 | 7.8 | High | CNA |
| CVSS 3.1 | 7.1 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: tracing: Fix reading strings from synthetic events The follow commands caused a crash: # cd /sys/kernel/tracing # echo 's:open char file[]' > dynamic_events # echo 'hist:keys=common_pid:file=filename:onchange($file).trace(open,$file)' > events/syscalls/sys_enter_openat/trigger' # echo 1 > events/synthetic/open/enable BOOM! The problem is that the synthetic event field "char file[]" will read the value given to it as a string without any memory checks to make sure the address is valid. The above example will pass in the user space address and the sythetic event code will happily call strlen() on it and then strscpy() where either one will cause an oops when accessing user space addresses. Use the helper functions from trace_kprobe and trace_eprobe that can read strings safely (and actually succeed when the address is from user space and the memory is mapped in). Now the above can show: packagekitd-1721 [000] ...2. 104.597170: open: file=/usr/lib/rpm/fileattrs/cmake.attr in:imjournal-978 [006] ...2. 104.599642: open: file=/var/lib/rsyslog/imjournal.state.tmp packagekitd-1721 [000] ...2. 104.626308: open: file=/usr/lib/rpm/fileattrs/debuginfo.attr
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Out-of-bounds Read
The product reads data past the end, or before the beginning, of the intended buffer.
How developers prevent this class of flaw
- Use a language that provides appropriate memory abstractions.
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 Out-of-bounds Read vulnerabilities
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
- 7.1 High severity
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