Linux: Use After Free
CVE-2023-52757 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 99f476e27aad5964ab13777d84fda67d1356dec1, ce49569079a9d4cad26c0f1d4653382fd9a5ca7a, 9eb44db68c5b7f5aa22b8fc7de74a3e2e08d1f29 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 0.19% 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 99f476e27aad5964ab13777d84fda67d1356dec1 or ce49569079a9d4cad26c0f1d4653382fd9a5ca7a or 9eb44db68c5b7f5aa22b8fc7de74a3e2e08d1f29 or b9bb9607b1fc12fca51f5632da25b36975f599bf, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.237 or 5.15.181 or 6.1.64 or 6.5.13, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 7b71843fa7028475b052107664cbe120156a2cfc up to, but not including, 99f476e27aad5964ab13777d84fda67d1356dec1; 7b71843fa7028475b052107664cbe120156a2cfc up to, but not including, ce49569079a9d4cad26c0f1d4653382fd9a5ca7a; 7b71843fa7028475b052107664cbe120156a2cfc up to, but not including, 9eb44db68c5b7f5aa22b8fc7de74a3e2e08d1f29; 7b71843fa7028475b052107664cbe120156a2cfc up to, but not including, b9bb9607b1fc12fca51f5632da25b36975f599bf; 7b71843fa7028475b052107664cbe120156a2cfc up to, but not including, c1a5962f1462b64fe7b69f20a4b6af8067bc2d26; 7b71843fa7028475b052107664cbe120156a2cfc up to, but not including, e6322fd177c6885a21dd4609dc5e5c973d1a2eb7; 9871dea42034ee6e73bb2b97ba0284d3d462b230; 5.4.6 up to, but not including, 5.5; and 1 more ranges | 99f476e27aad5964ab13777d84fda67d1356dec1, ce49569079a9d4cad26c0f1d4653382fd9a5ca7a, 9eb44db68c5b7f5aa22b8fc7de74a3e2e08d1f29, b9bb9607b1fc12fca51f5632da25b36975f599bf, c1a5962f1462b64fe7b69f20a4b6af8067bc2d26, e6322fd177c6885a21dd4609dc5e5c973d1a2eb7 |
| Debian | Debian Linux | 11.0 | Not stated |
| Linux | Linux Kernel | before 5.10.237; 5.11 up to, but not including, 5.15.181; 5.16 up to, but not including, 6.1.64; 6.2 up to, but not including, 6.5.13; 6.6 up to, but not including, 6.6.3 | 5.10.237, 5.15.181, 6.1.64, 6.5.13, 6.6.3 |
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
- 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.
Official description
In the Linux kernel, the following vulnerability has been resolved: smb: client: fix potential deadlock when releasing mids All release_mid() callers seem to hold a reference of @mid so there is no need to call kref_put(&mid->refcount, __release_mid) under @server->mid_lock spinlock. If they don't, then an use-after-free bug would have occurred anyways. By getting rid of such spinlock also fixes a potential deadlock as shown below CPU 0 CPU 1 ------------------------------------------------------------------ cifs_demultiplex_thread() cifs_debug_data_proc_show() release_mid() spin_lock(&server->mid_lock); spin_lock(&cifs_tcp_ses_lock) spin_lock(&server->mid_lock) __release_mid() smb2_find_smb_tcon() spin_lock(&cifs_tcp_ses_lock) *deadlock*
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: partial).
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/99f476e27aad5964ab13777d84fda67d1356dec1
- git.kernel.org/stable/c/9eb44db68c5b7f5aa22b8fc7de74a3e2e08d1f29
- git.kernel.org/stable/c/b9bb9607b1fc12fca51f5632da25b36975f599bf
- git.kernel.org/stable/c/c1a5962f1462b64fe7b69f20a4b6af8067bc2d26
- git.kernel.org/stable/c/ce49569079a9d4cad26c0f1d4653382fd9a5ca7a
- git.kernel.org/stable/c/e6322fd177c6885a21dd4609dc5e5c973d1a2eb7
Third-party and government advisories
- lists.debian.org/debian-lts-announce/2025/05/msg00030.htmlMailing List, Third Party Advisory
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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