Linux: Double Free
CVE-2025-37915 is a high-severity double free vulnerability in Linux, with a CVSS 3.1 base score of 7.0 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 5da3aad1a13e7edb8ff0778a444ccf49930313e9, 4b07ac06b0a712923255aaf2691637693fc7100d, 2968632880f1792007eedd12eeedf7f6e2b7e9f3 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 0.22% 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 5da3aad1a13e7edb8ff0778a444ccf49930313e9 or 4b07ac06b0a712923255aaf2691637693fc7100d or 2968632880f1792007eedd12eeedf7f6e2b7e9f3 or 4f0ecf50cdf76da95828578a92f130b653ac2fcf, whichever matches your release line, or a later version.
- Update Linux Kernel to 5.4.294 or 5.10.238 or 5.15.182 or 6.1.138, whichever matches your release line, or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, 5da3aad1a13e7edb8ff0778a444ccf49930313e9; 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, 4b07ac06b0a712923255aaf2691637693fc7100d; 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, 2968632880f1792007eedd12eeedf7f6e2b7e9f3; 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, 4f0ecf50cdf76da95828578a92f130b653ac2fcf; 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, db205b92dfe0501e5b92fb7cf00971d0e44ba3eb; 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, 26e75716b94d6ff9be5ea07d63675c4d189f30b4; 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, ab2248110738d4429668140ad22f530a9ee730e1; 37d9cf1a3ce35de3df6f7d209bfb1f50cf188cea up to, but not including, f99a3fbf023e20b626be4b0f042463d598050c9a; and 1 more ranges | 5da3aad1a13e7edb8ff0778a444ccf49930313e9, 4b07ac06b0a712923255aaf2691637693fc7100d, 2968632880f1792007eedd12eeedf7f6e2b7e9f3, 4f0ecf50cdf76da95828578a92f130b653ac2fcf, db205b92dfe0501e5b92fb7cf00971d0e44ba3eb, 26e75716b94d6ff9be5ea07d63675c4d189f30b4 |
| Linux | Linux Kernel | 5.0.1 up to, but not including, 5.4.294; 5.5 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; 5.0; and 1 more ranges | 5.4.294, 5.10.238, 5.15.182, 6.1.138, 6.6.90, 6.12.28 |
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
- HighSuccess depends on conditions outside the attacker's control.
- 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:H/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 | 7.0 | High | NVD |
Official description
In the Linux kernel, the following vulnerability has been resolved: net_sched: drr: 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 drr, 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 adding to the list to cover 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/26e75716b94d6ff9be5ea07d63675c4d189f30b4
- git.kernel.org/stable/c/2968632880f1792007eedd12eeedf7f6e2b7e9f3
- git.kernel.org/stable/c/4b07ac06b0a712923255aaf2691637693fc7100d
- git.kernel.org/stable/c/4f0ecf50cdf76da95828578a92f130b653ac2fcf
- git.kernel.org/stable/c/5da3aad1a13e7edb8ff0778a444ccf49930313e9
- git.kernel.org/stable/c/ab2248110738d4429668140ad22f530a9ee730e1
- git.kernel.org/stable/c/db205b92dfe0501e5b92fb7cf00971d0e44ba3eb
- git.kernel.org/stable/c/f99a3fbf023e20b626be4b0f042463d598050c9a
Other references
Recent Double 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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