Linux: Use After Free
CVE-2025-22083 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 451c72f5e7cf5d339a6410a635cee0825687c3dc, 2b34bdc42df047794542f3e220fe989124e4499a, 3a19eb3d9818e28f14c818a18dc913344a52ca92 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 0.21% 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 451c72f5e7cf5d339a6410a635cee0825687c3dc or 2b34bdc42df047794542f3e220fe989124e4499a or 3a19eb3d9818e28f14c818a18dc913344a52ca92 or 3fd054baf382a426bbf5135ede0fc5673db74d3e, whichever matches your release line, or a later version.
- Update Linux Kernel to 6.6.87 or 6.12.23 or 6.13.11 or 6.14.2, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 4f7f46d32c9875004fae1d57ae3c02cc2e6cd6a3 up to, but not including, 451c72f5e7cf5d339a6410a635cee0825687c3dc; 4f7f46d32c9875004fae1d57ae3c02cc2e6cd6a3 up to, but not including, 2b34bdc42df047794542f3e220fe989124e4499a; 4f7f46d32c9875004fae1d57ae3c02cc2e6cd6a3 up to, but not including, 3a19eb3d9818e28f14c818a18dc913344a52ca92; 4f7f46d32c9875004fae1d57ae3c02cc2e6cd6a3 up to, but not including, 3fd054baf382a426bbf5135ede0fc5673db74d3e; 4f7f46d32c9875004fae1d57ae3c02cc2e6cd6a3 up to, but not including, 63b449f73ab0dcc0ba11ceaa4c5c70bc86ccf03c; 4f7f46d32c9875004fae1d57ae3c02cc2e6cd6a3 up to, but not including, 5dd639a1646ef5fe8f4bf270fad47c5c3755b9b6; 3.9 | 451c72f5e7cf5d339a6410a635cee0825687c3dc, 2b34bdc42df047794542f3e220fe989124e4499a, 3a19eb3d9818e28f14c818a18dc913344a52ca92, 3fd054baf382a426bbf5135ede0fc5673db74d3e, 63b449f73ab0dcc0ba11ceaa4c5c70bc86ccf03c, 5dd639a1646ef5fe8f4bf270fad47c5c3755b9b6 |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518-4 PN/DP MFP (6ES7518-4AX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AB0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIMATIC S7-1500 CPU 1518F-4 PN/DP MFP (6ES7518-4FX00-1AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Siemens | SIPLUS S7-1500 CPU 1518-4 PN/DP MFP (6AG1518-4AX00-4AC0) | V3.1.6 and later; V3.1.7 and later | Not stated |
| Linux | Linux Kernel | 3.9.1 up to, but not including, 6.6.87; 6.7 up to, but not including, 6.12.23; 6.13 up to, but not including, 6.13.11; 6.14 up to, but not including, 6.14.2; 3.9 | 6.6.87, 6.12.23, 6.13.11, 6.14.2 |
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 | 7.8 | High | CNA |
| CVSS 3.1 | 7.8 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: vhost-scsi: Fix handling of multiple calls to vhost_scsi_set_endpoint If vhost_scsi_set_endpoint is called multiple times without a vhost_scsi_clear_endpoint between them, we can hit multiple bugs found by Haoran Zhang: 1. Use-after-free when no tpgs are found: This fixes a use after free that occurs when vhost_scsi_set_endpoint is called more than once and calls after the first call do not find any tpgs to add to the vs_tpg. When vhost_scsi_set_endpoint first finds tpgs to add to the vs_tpg array match=true, so we will do: vhost_vq_set_backend(vq, vs_tpg); ... kfree(vs->vs_tpg); vs->vs_tpg = vs_tpg; If vhost_scsi_set_endpoint is called again and no tpgs are found match=false so we skip the vhost_vq_set_backend call leaving the pointer to the vs_tpg we then free via: kfree(vs->vs_tpg); vs->vs_tpg = vs_tpg; If a scsi request is then sent we do: vhost_scsi_handle_vq -> vhost_scsi_get_req -> vhost_vq_get_backend which sees the vs_tpg we just did a kfree on. 2. Tpg dir removal hang: This patch fixes an issue where we cannot remove a LIO/target layer tpg (and structs above it like the target) dir due to the refcount dropping to -1. The problem is that if vhost_scsi_set_endpoint detects a tpg is already in the vs->vs_tpg array or if the tpg has been removed so target_depend_item fails, the undepend goto handler will do target_undepend_item on all tpgs in the vs_tpg array dropping their refcount to 0. At this time vs_tpg contains both the tpgs we have added in the current vhost_scsi_set_endpoint call as well as tpgs we added in previous calls which are also in vs->vs_tpg. Later, when vhost_scsi_clear_endpoint runs it will do target_undepend_item on all the tpgs in the vs->vs_tpg which will drop their refcount to -1. Userspace will then not be able to remove the tpg and will hang when it tries to do rmdir on the tpg dir. 3. Tpg leak: This fixes a bug where we can leak tpgs and cause them to be un-removable because the target name is overwritten when vhost_scsi_set_endpoint is called multiple times but with different target names. The bug occurs if a user has called VHOST_SCSI_SET_ENDPOINT and setup a vhost-scsi device to target/tpg mapping, then calls VHOST_SCSI_SET_ENDPOINT again with a new target name that has tpgs we haven't seen before (target1 has tpg1 but target2 has tpg2). When this happens we don't teardown the old target tpg mapping and just overwrite the target name and the vs->vs_tpg array. Later when we do vhost_scsi_clear_endpoint, we are passed in either target1 or target2's name and we will only match that target's tpgs when we loop over the vs->vs_tpg. We will then return from the function without doing target_undepend_item on the tpgs. Because of all these bugs, it looks like being able to call vhost_scsi_set_endpoint multiple times was never supported. The major user, QEMU, already has checks to prevent this use case. So to fix the issues, this patch prevents vhost_scsi_set_endpoint from being called if it's already successfully added tpgs. To add, remove or change the tpg config or target name, you must do a vhost_scsi_clear_endpoint first.
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.
- Record last changed materially (score, affected products, status or references).
References
Patches and release notes
- git.kernel.org/stable/c/2b34bdc42df047794542f3e220fe989124e4499a
- git.kernel.org/stable/c/3a19eb3d9818e28f14c818a18dc913344a52ca92
- git.kernel.org/stable/c/3fd054baf382a426bbf5135ede0fc5673db74d3e
- git.kernel.org/stable/c/451c72f5e7cf5d339a6410a635cee0825687c3dc
- git.kernel.org/stable/c/5dd639a1646ef5fe8f4bf270fad47c5c3755b9b6
- git.kernel.org/stable/c/63b449f73ab0dcc0ba11ceaa4c5c70bc86ccf03c
Other references
Recent Use After Free vulnerabilities
- 8.8 High severity
- 7.8 High severity
- 7.8 High severity
- 9.8 Critical severity
- 7.8 High severity
- 7.8 High severity
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