UBUNTU-CVE-2025-37797

Advisory lineage Upstream: 1 Downstream: 32
Upstream
CVE-2025-37797
Published: 02 May 2025, 15:15
Last modified:10 Jul 2026, 02:24

Vulnerability Summary

Overall Risk (default)
medium
31/100
CVSS Score
7.8 HIGH
3.1 (osv_ubuntu)
EPSS Score
No data
KEV
Not listed
Ransomware
No reports
Public exploits
None found
Dark Web
Not detected

Timeline

02 May 2025, 15:15
Published
Vulnerability first disclosed
10 Jul 2026, 02:24
Last Modified
Vulnerability information updated

Description

In the Linux kernel, the following vulnerability has been resolved: net_sched: hfsc: Fix a UAF vulnerability in class handling This patch fixes a Use-After-Free vulnerability in the HFSC qdisc class handling. The issue occurs due to a time-of-check/time-of-use condition in hfsc_change_class() when working with certain child qdiscs like netem or codel. The vulnerability works as follows: 1. hfsc_change_class() checks if a class has packets (q.qlen != 0) 2. It then calls qdisc_peek_len(), which for certain qdiscs (e.g., codel, netem) might drop packets and empty the queue 3. The code continues assuming the queue is still non-empty, adding the class to vttree 4. This breaks HFSC scheduler assumptions that only non-empty classes are in vttree 5. Later, when the class is destroyed, this can lead to a Use-After-Free The fix adds a second queue length check after qdisc_peek_len() to verify the queue wasn't emptied.

CVSS Metrics

  • v3.1•HIGH•Score: 7.8CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H

Affected Systems

  • ubuntu•linux

    < 4.15.0-240.252 | < 5.4.0-220.240 | < 5.15.0-144.157 | < 6.8.0-71.71

  • ubuntu•linux-allwinner-5.19

    all

  • ubuntu•linux-aws

    < 4.15.0-1183.196 | < 5.4.0-1149.159 | < 5.15.0-1088.95 | < 6.8.0-1033.35

  • ubuntu•linux-aws-5.0

    all

  • ubuntu•linux-aws-5.11

    all

  • ubuntu•linux-aws-5.13

    all

  • ubuntu•linux-aws-5.15

    < 5.15.0-1088.95~20.04.1

  • ubuntu•linux-aws-5.19

    all

  • ubuntu•linux-aws-5.3

    all

  • ubuntu•linux-aws-5.4

    < 5.4.0-1149.159~18.04.1

  • ubuntu•linux-aws-5.8

    all

  • ubuntu•linux-aws-6.2

    all

  • ubuntu•linux-aws-6.5

    all

  • ubuntu•linux-aws-6.8

    < 6.8.0-1033.35~22.04.1

  • ubuntu•linux-aws-fips

    < 4.15.0-2121.127 | all | < 5.4.0-1149.159+fips1 | < 5.15.0-1088.95+fips1

  • ubuntu•linux-aws-hwe

    < 4.15.0-1183.196~16.04.1

  • ubuntu•linux-azure

    < 4.15.0-1191.206~14.04.1 | < 4.15.0-1191.206~16.04.1 | all | < 5.4.0-1154.161 | < 5.15.0-1094.103 | < 6.8.0-1034.39

  • ubuntu•linux-azure-4.15

    < 4.15.0-1191.206

  • ubuntu•linux-azure-5.11

    all

  • ubuntu•linux-azure-5.13

    all

  • ubuntu•linux-azure-5.15

    < 5.15.0-1094.103~20.04.1

  • ubuntu•linux-azure-5.19

    all

  • ubuntu•linux-azure-5.3

    all

  • ubuntu•linux-azure-5.4

    < 5.4.0-1154.161~18.04.1

  • ubuntu•linux-azure-5.8

    all

  • ubuntu•linux-azure-6.11

    all

  • ubuntu•linux-azure-6.2

    all

  • ubuntu•linux-azure-6.5

    all

  • ubuntu•linux-azure-6.8

    < 6.8.0-1034.39~22.04.1

  • ubuntu•linux-azure-edge

    all

  • ubuntu•linux-azure-fde

    all | all | all

  • ubuntu•linux-azure-fde-5.19

    all

  • ubuntu•linux-azure-fde-6.17

    all

  • ubuntu•linux-azure-fde-6.2

    all

  • ubuntu•linux-azure-fips

    < 4.15.0-2100.106 | all | < 5.4.0-1155.162+fips1 | < 5.15.0-1094.103+fips1

  • ubuntu•linux-azure-nvidia

    < 6.8.0-1022.23

  • ubuntu•linux-bluefield

    < 5.15.0-1072.74 | < 5.4.0-1108.115 | < 5.15.0-1072.74 | all

  • ubuntu•linux-fips

    < 4.15.0-1138.149 | all | < 5.4.0-1123.133 | < 5.15.0-144.157+fips1 | < 6.8.0-78.78+fips1

  • ubuntu•linux-gcp

    < 4.15.0-1176.193~16.04.1 | all | < 5.4.0-1152.161 | < 5.15.0-1087.96 | < 6.8.0-1034.36

  • ubuntu•linux-gcp-4.15

    < 4.15.0-1176.193

  • ubuntu•linux-gcp-5.11

    all

  • ubuntu•linux-gcp-5.13

    all

  • ubuntu•linux-gcp-5.15

    < 5.15.0-1087.96~20.04.2

  • ubuntu•linux-gcp-5.19

    all

  • ubuntu•linux-gcp-5.3

    all

  • ubuntu•linux-gcp-5.4

    < 5.4.0-1152.161~18.04.1

  • ubuntu•linux-gcp-5.8

    all

  • ubuntu•linux-gcp-6.11

    all

  • ubuntu•linux-gcp-6.14

    < 6.14.0-1011.11~24.04.1

  • ubuntu•linux-gcp-6.2

    all

Showing first 50 affected entries in server-rendered view.

References (43)