bpf: Fix OOB in pcpu_init_value
Affects Linux kernel BPF setups that combine a cgroup storage map with a value size not a multiple of 8 bytes and a per-CPU map of the same size. CVSS scores it 7.1 (high); no vendor rating is given.
- Published
- Last modified
- Where the record stands: published, rejected by its publisher, or superseded by another id.What do these mean? →
- published
- Whether CISA lists it in its Known Exploited Vulnerabilities catalog: proof that attackers are using it.What do these mean? →
- Not listed in CISA KEV
- How many real-world setups can hit the bug, from the vendor's advisory and CISA data. It does not know your setup.What do these mean? →
- Specific setups only
- Fix
- Fixed in 5.5, 5.10, 6.6.141, 6.12.91, 6.18.33, and 1 more
- Whether working attack code is public (Exploit-DB, Metasploit, Nuclei or GitHub). Public code makes attacks easier.What do these mean? →
- None on Exploit-DB, Metasploit or GitHub
- Exploitation: none
- Automatable: no
- Technical impact: partial
Summary
In the Linux kernel, the following vulnerability has been resolved: bpf: Fix OOB in pcpu_init_value An out-of-bounds read occurs when copying element from a BPF_MAP_TYPE_CGROUP_STORAGE map to another pcpu map with the same value_size that is not rounded up to 8 bytes. The issue happens when: 1. A CGROUP_STORAGE map is created with value_size not aligned to 8 bytes (e.g., 4 bytes) 2. A pcpu map is created with the same value_size (e.g., 4 bytes) 3. Update element in 2 with data in 1 pcpu_init_value assumes that all sources are rounded up to 8 bytes, and invokes copy_map_value_long to make a data copy, However, the assumption doesn't stand since there are some cases where the source may not be rounded up to 8 bytes, e.g., CGROUP_STORAGE, skb->data. the verifier verifies exactly the size that the source claims, not the size rounded up to 8 bytes by kernel, an OOB happens when the source has only 4 bytes while the copy size(4) is rounded up to 8.
Timeline
- CVE published
- CISA SSVC assessment
Exploitation: none · Automatable: no · Technical impact: partial
- Record last updated
Affected versions
- Linux Linux
From 5.4.78 · fixed in 5.5; From 5.9.9 · fixed in 5.10
- Linux Linux
5.10
- KernelLinux
From 5.10.0 · fixed in 6.6.141; From 6.7.0 · fixed in 6.12.91; From 6.13.0 · fixed in 6.18.33; From 6.19.0 · fixed in 7.0.10
References 6
git.kernel.org
Questions about CVE-2026-53076
What does this mean?
The bug is an out-of-bounds read in the BPF kernel code. When a per-CPU map element is updated with data from a cgroup storage map, the copy size is rounded up to 8 bytes even when the source holds fewer bytes, so the copy reads past the end of the source data.Source: git.kernel.org
Am I affected, and how do I check?
The listed affected kernel ranges are 5.4.78 up to 5.5, 5.9.9 up to 5.10, and 5.10.0 up to 6.6.141, 6.7.0 up to 6.12.91, 6.13.0 up to 6.18.33, and 6.19.0 up to 7.0.10. To check a system, run uname -r to see the kernel version, and check whether BPF cgroup storage maps are created with a value_size that is not a multiple of 8 bytes, such as 4 bytes.Source: git.kernel.org
What should I do about it?
Update to a kernel release at or past the fixed version for your branch: 5.5 or 5.10 for the older entries, 6.6.141, 6.12.91, 6.18.33, or 7.0.10 for the later series. The sources provided do not describe a workaround.Source: git.kernel.org
Is it being exploited?
It is not in CISA's Known Exploited Vulnerabilities catalog, and CISA's SSVC assessment does not mark exploitation as active. That does not mean it has not been attacked: vendors and researchers can report attacks before CISA lists them. No public exploit code is tracked.Source: cve.now feed data