Linux: Use After Free
CVE-2024-53206 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 2dcc86fefe09ac853158afd96b60d544af115dc5, 9a3c1ad93e6fba67b3a637cfa95a57a6685e4908, 65ed89cad1f57034c256b016e89e8c0a4ec7c65b 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 0.63% chance of exploitation within 30 days, higher than 51% of scored CVEs.
High severity with no evidence of exploitation so far.
What to do
- Update Linux to 2dcc86fefe09ac853158afd96b60d544af115dc5 or 9a3c1ad93e6fba67b3a637cfa95a57a6685e4908 or 65ed89cad1f57034c256b016e89e8c0a4ec7c65b or d0eb14cb8c08b00c36a3d5dc57a6f428b301f721, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.15.174 or 6.1.120 or 6.6.64 or 6.11.11, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 8459d61fbf24967839a70235165673148c7c7f17 up to, but not including, 2dcc86fefe09ac853158afd96b60d544af115dc5; 5071beb59ee416e8ab456ac8647a4dabcda823b1 up to, but not including, 9a3c1ad93e6fba67b3a637cfa95a57a6685e4908; 997ae8da14f1639ce6fb66a063dab54031cd61b3 up to, but not including, 65ed89cad1f57034c256b016e89e8c0a4ec7c65b; 51e34db64f4e43c7b055ccf881b7f3e0c31bb26d up to, but not including, d0eb14cb8c08b00c36a3d5dc57a6f428b301f721; e8c526f2bdf1845bedaf6a478816a3d06fa78b8f up to, but not including, 6d845028609a4af0ad66f499ee0bd5789122b067; e8c526f2bdf1845bedaf6a478816a3d06fa78b8f up to, but not including, c31e72d021db2714df03df6c42855a1db592716c; 106e457953315e476b3642ef24be25ed862aaba3; c964bf65f80a14288d767023a1b300b30f5b9cd0; and 7 more ranges | 2dcc86fefe09ac853158afd96b60d544af115dc5, 9a3c1ad93e6fba67b3a637cfa95a57a6685e4908, 65ed89cad1f57034c256b016e89e8c0a4ec7c65b, d0eb14cb8c08b00c36a3d5dc57a6f428b301f721, 6d845028609a4af0ad66f499ee0bd5789122b067, c31e72d021db2714df03df6c42855a1db592716c |
| Linux | Linux Kernel | 5.15.170 up to, but not including, 5.15.174; 6.1.115 up to, but not including, 6.1.120; 6.6.59 up to, but not including, 6.6.64; 6.11.6 up to, but not including, 6.11.11; 6.12 up to, but not including, 6.12.2 | 5.15.174, 6.1.120, 6.6.64, 6.11.11, 6.12.2 |
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 |
| CVSS 3.1 | 7.8 | High | CISA (ADP) |
Official description
In the Linux kernel, the following vulnerability has been resolved: tcp: Fix use-after-free of nreq in reqsk_timer_handler(). The cited commit replaced inet_csk_reqsk_queue_drop_and_put() with __inet_csk_reqsk_queue_drop() and reqsk_put() in reqsk_timer_handler(). Then, oreq should be passed to reqsk_put() instead of req; otherwise use-after-free of nreq could happen when reqsk is migrated but the retry attempt failed (e.g. due to timeout). Let's pass oreq to reqsk_put().
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/2dcc86fefe09ac853158afd96b60d544af115dc5
- git.kernel.org/stable/c/65ed89cad1f57034c256b016e89e8c0a4ec7c65b
- git.kernel.org/stable/c/6d845028609a4af0ad66f499ee0bd5789122b067
- git.kernel.org/stable/c/9a3c1ad93e6fba67b3a637cfa95a57a6685e4908
- git.kernel.org/stable/c/c31e72d021db2714df03df6c42855a1db592716c
- git.kernel.org/stable/c/d0eb14cb8c08b00c36a3d5dc57a6f428b301f721
Other references
Recent Use After Free vulnerabilities
- 7.8 High severity
- 7.0 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
- 7.8 High severity
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