CyberSecBulletin
CVE-2025-38502NVD status: Modified

Linux: Out-of-bounds Read

Published Updated By the CyberSecBulletin desk

CVE-2025-38502 is a high-severity out-of-bounds read vulnerability in Linux, with a CVSS 3.1 base score of 7.1 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 c1c74584b9b4043c52e41fec415226e582d266a3, 66da7cee78590259b400e51a70622ccd41da7bb2, 7acfa07c585e3d7a64654d38f0a5c762877d0b9b 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 0.19% chance of exploitation within 30 days, which is low compared with other CVEs.

Next patch cycle

High severity with no evidence of exploitation so far.

What to do

  1. Update Linux to c1c74584b9b4043c52e41fec415226e582d266a3 or 66da7cee78590259b400e51a70622ccd41da7bb2 or 7acfa07c585e3d7a64654d38f0a5c762877d0b9b or 41688d1fc5d163a6c2c0e95c0419e2cb31a44648, whichever matches your release line, or a later version.
  2. Update SIMATIC CN 4100 to V5.0 or a later version.
  3. Update Linux Kernel to 5.15.192 or 6.1.151 or 6.6.105 or 6.12.46, whichever matches your release line, or a later version.

Affected products and versions

VendorProductAffected versionsFixed in
LinuxLinux7d9c3427894fe70d1347b4820476bf37736d2ff0 up to, but not including, c1c74584b9b4043c52e41fec415226e582d266a3; 7d9c3427894fe70d1347b4820476bf37736d2ff0 up to, but not including, 66da7cee78590259b400e51a70622ccd41da7bb2; 7d9c3427894fe70d1347b4820476bf37736d2ff0 up to, but not including, 7acfa07c585e3d7a64654d38f0a5c762877d0b9b; 7d9c3427894fe70d1347b4820476bf37736d2ff0 up to, but not including, 41688d1fc5d163a6c2c0e95c0419e2cb31a44648; 7d9c3427894fe70d1347b4820476bf37736d2ff0 up to, but not including, 19341d5c59e8c7e8528e40f8663e99d67810473c; 7d9c3427894fe70d1347b4820476bf37736d2ff0 up to, but not including, abad3d0bad72a52137e0c350c59542d75ae4f513; 5.9c1c74584b9b4043c52e41fec415226e582d266a3, 66da7cee78590259b400e51a70622ccd41da7bb2, 7acfa07c585e3d7a64654d38f0a5c762877d0b9b, 41688d1fc5d163a6c2c0e95c0419e2cb31a44648, 19341d5c59e8c7e8528e40f8663e99d67810473c, abad3d0bad72a52137e0c350c59542d75ae4f513
SiemensSIMATIC CN 4100before V5.0V5.0
LinuxLinux Kernel5.9 up to, but not including, 5.15.192; 5.16 up to, but not including, 6.1.151; 6.2 up to, but not including, 6.6.105; 6.7 up to, but not including, 6.12.46; 6.13 up to, but not including, 6.16.15.15.192, 6.1.151, 6.6.105, 6.12.46, 6.16.1
DebianDebian Linux11.0Not stated
SiemensSimatic Cn 4100 Firmwarebefore 5.05.0

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
NoneNothing can be modified.
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:N/A:H. Scored by NVD.

Scoring systemScoreSeverityScored by
CVSS 3.17.8HighCNA
CVSS 3.17.1HighNVD

Official description

In the Linux kernel, the following vulnerability has been resolved: bpf: Fix oob access in cgroup local storage Lonial reported that an out-of-bounds access in cgroup local storage can be crafted via tail calls. Given two programs each utilizing a cgroup local storage with a different value size, and one program doing a tail call into the other. The verifier will validate each of the indivial programs just fine. However, in the runtime context the bpf_cg_run_ctx holds an bpf_prog_array_item which contains the BPF program as well as any cgroup local storage flavor the program uses. Helpers such as bpf_get_local_storage() pick this up from the runtime context: ctx = container_of(current->bpf_ctx, struct bpf_cg_run_ctx, run_ctx); storage = ctx->prog_item->cgroup_storage[stype]; if (stype == BPF_CGROUP_STORAGE_SHARED) ptr = &READ_ONCE(storage->buf)->data[0]; else ptr = this_cpu_ptr(storage->percpu_buf); For the second program which was called from the originally attached one, this means bpf_get_local_storage() will pick up the former program's map, not its own. With mismatching sizes, this can result in an unintended out-of-bounds access. To fix this issue, we need to extend bpf_map_owner with an array of storage_cookie[] to match on i) the exact maps from the original program if the second program was using bpf_get_local_storage(), or ii) allow the tail call combination if the second program was not using any of the cgroup local storage maps.

Source: the CVE record as published by its numbering authority, via NVD and CVE.org.

The underlying weakness: Out-of-bounds Read

The product reads data past the end, or before the beginning, of the intended buffer.

How developers prevent this class of flaw

  • Use a language that provides appropriate memory abstractions.

More Out-of-bounds Read vulnerabilities (CWE-125)

Timeline

  1. CVE record published.
  2. CISA published its SSVC assessment (exploitation: none, automatable: no, technical impact: total).
  3. Record last changed materially (score, affected products, status or references).

References

Third-party and government advisories

Recent Out-of-bounds Read vulnerabilities

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