Linux: Use After Free
CVE-2026-53089 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 43d6848a2a6c92ccfd614d9f0bb6fd85b95dfa9d, 642943ae5bdacabc8109dc4a5e0ebb4a6b99ef3e, fea55b034328feaafef75aee252f305e6f85a991 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 0.12% 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 43d6848a2a6c92ccfd614d9f0bb6fd85b95dfa9d or 642943ae5bdacabc8109dc4a5e0ebb4a6b99ef3e or fea55b034328feaafef75aee252f305e6f85a991 or 5662dac41a3442aa378d7c405164903eb109fc05, whichever matches your release line, or a later version.
- Update Linux Kernel to 7.0.10 or a later version.
Affected products and versions
| Vendor | Product | Affected versions | Fixed in |
|---|---|---|---|
| Linux | Linux | 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, 43d6848a2a6c92ccfd614d9f0bb6fd85b95dfa9d; 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, 642943ae5bdacabc8109dc4a5e0ebb4a6b99ef3e; 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, fea55b034328feaafef75aee252f305e6f85a991; 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, 5662dac41a3442aa378d7c405164903eb109fc05; 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, 1a2dc103e16448d022a77ad5fc3234641436c4b7; 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, 85dc711f742b192eb97c0e00b521312f5a7a415e; 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, a51e7fbe94a87e236631a83973d4f558310b2cd2; 675fc275a3a2d905535207237402c6d8dcb5fa4b up to, but not including, a0c584fc18056709c8e047a82a6045d6c209f4ce; and 1 more ranges | 43d6848a2a6c92ccfd614d9f0bb6fd85b95dfa9d, 642943ae5bdacabc8109dc4a5e0ebb4a6b99ef3e, fea55b034328feaafef75aee252f305e6f85a991, 5662dac41a3442aa378d7c405164903eb109fc05, 1a2dc103e16448d022a77ad5fc3234641436c4b7, 85dc711f742b192eb97c0e00b521312f5a7a415e |
| Linux | Linux Kernel | 4.16 up to, but not including, 7.0.10 | 7.0.10 |
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: bpf: Fix use-after-free in offloaded map/prog info fill When querying info for an offloaded BPF map or program, bpf_map_offload_info_fill_ns() and bpf_prog_offload_info_fill_ns() obtain the network namespace with get_net(dev_net(offmap->netdev)). However, the associated netdev's netns may be racing with teardown during netns destruction. If the netns refcount has already reached 0, get_net() performs a refcount_t increment on 0, triggering: refcount_t: addition on 0; use-after-free. Although rtnl_lock and bpf_devs_lock ensure the netdev pointer remains valid, they cannot prevent the netns refcount from reaching zero. Fix this by using maybe_get_net() instead of get_net(). maybe_get_net() uses refcount_inc_not_zero() and returns NULL if the refcount is already zero, which causes ns_get_path_cb() to fail and the caller to return -ENOENT -- the correct behavior when the netns is being destroyed.
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
Other references
- git.kernel.org/stable/c/1a2dc103e16448d022a77ad5fc3234641436c4b7
- git.kernel.org/stable/c/43d6848a2a6c92ccfd614d9f0bb6fd85b95dfa9d
- git.kernel.org/stable/c/5662dac41a3442aa378d7c405164903eb109fc05
- git.kernel.org/stable/c/642943ae5bdacabc8109dc4a5e0ebb4a6b99ef3e
- git.kernel.org/stable/c/85dc711f742b192eb97c0e00b521312f5a7a415e
- git.kernel.org/stable/c/fea55b034328feaafef75aee252f305e6f85a991
Recent Use After Free vulnerabilities
- 7.5 High severity
- 8.8 High severity
- 7.8 High severity
- 8.8 High severity
- 8.8 High severity
- 9.6 Critical severity
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