Linux: Double Free
CVE-2025-37914 is a high-severity double 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 24388ba0a1b1b6d4af1b205927ac7f7b119ee4ea, 554acc5a2ea9703e08023eb9a003f9e5a830a502, 9efb6a0fa88e0910d079fdfeb4f7ce4d4ac6c990 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 0.23% 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 24388ba0a1b1b6d4af1b205927ac7f7b119ee4ea or 554acc5a2ea9703e08023eb9a003f9e5a830a502 or 9efb6a0fa88e0910d079fdfeb4f7ce4d4ac6c990 or 72c3da7e6ceb74e74ddbb5a305a35c9fdfcac6e3, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.10.238 or 5.15.182 or 6.1.138 or 6.6.90, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 up to, but not including, 24388ba0a1b1b6d4af1b205927ac7f7b119ee4ea; dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 up to, but not including, 554acc5a2ea9703e08023eb9a003f9e5a830a502; dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 up to, but not including, 9efb6a0fa88e0910d079fdfeb4f7ce4d4ac6c990; dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 up to, but not including, 72c3da7e6ceb74e74ddbb5a305a35c9fdfcac6e3; dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 up to, but not including, 1f01e9f961605eb397c6ecd1d7b0233dfbf9077c; dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 up to, but not including, bc321f714de693aae06e3786f88df2975376d996; dcc68b4d8084e1ac9af0d4022d6b1aff6a139a33 up to, but not including, 1a6d0c00fa07972384b0c308c72db091d49988b6; 5.6 | 24388ba0a1b1b6d4af1b205927ac7f7b119ee4ea, 554acc5a2ea9703e08023eb9a003f9e5a830a502, 9efb6a0fa88e0910d079fdfeb4f7ce4d4ac6c990, 72c3da7e6ceb74e74ddbb5a305a35c9fdfcac6e3, 1f01e9f961605eb397c6ecd1d7b0233dfbf9077c, bc321f714de693aae06e3786f88df2975376d996 |
| Linux | Linux Kernel | 5.6 up to, but not including, 5.10.238; 5.11 up to, but not including, 5.15.182; 5.16 up to, but not including, 6.1.138; 6.2 up to, but not including, 6.6.90; 6.7 up to, but not including, 6.12.28; 6.13 up to, but not including, 6.14.6; 6.15 | 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28, 6.14.6 |
| Debian | Debian Linux | 11.0 | Not stated |
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: net_sched: ets: Fix double list add in class with netem as child qdisc As described in Gerrard's report [1], there are use cases where a netem child qdisc will make the parent qdisc's enqueue callback reentrant. In the case of ets, there won't be a UAF, but the code will add the same classifier to the list twice, which will cause memory corruption. In addition to checking for qlen being zero, this patch checks whether the class was already added to the active_list (cl_is_active) before doing the addition to cater for the reentrant case. [1] https://lore.kernel.org/netdev/CAHcdcOm+03OD2j6R0=YHKqmy=VgJ8xEOKuP6c7mSgnp-TEJJbw@mail.gmail.com/
Source: the CVE record as published by its numbering authority, via NVD and CVE.org.
The underlying weakness: Double Free
The product calls free() twice on the same memory address.
How developers prevent this class of flaw
- Choose a language that provides automatic memory management.
- Ensure that each allocation is freed only once. After freeing a chunk, set the pointer to NULL to ensure the pointer cannot be freed again. In complicated error conditions, be sure that clean-up routines respect the state of allocation properly. If the language is object oriented, ensure that object destructors delete each chunk of memory only once.
- Use a static analysis tool to find double free instances.
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/1a6d0c00fa07972384b0c308c72db091d49988b6
- git.kernel.org/stable/c/1f01e9f961605eb397c6ecd1d7b0233dfbf9077c
- git.kernel.org/stable/c/24388ba0a1b1b6d4af1b205927ac7f7b119ee4ea
- git.kernel.org/stable/c/554acc5a2ea9703e08023eb9a003f9e5a830a502
- git.kernel.org/stable/c/72c3da7e6ceb74e74ddbb5a305a35c9fdfcac6e3
- git.kernel.org/stable/c/9efb6a0fa88e0910d079fdfeb4f7ce4d4ac6c990
- git.kernel.org/stable/c/bc321f714de693aae06e3786f88df2975376d996
Other references
Recent Double 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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