| Release Date: | 2025-10-01 | |
| Impact: | Moderate | What is this? |
In the Linux kernel, the following vulnerability has been resolved:
net_sched: gen_estimator: fix est_timer() vs CONFIG_PREEMPT_RT=y
syzbot reported a WARNING in est_timer() [1]
Problem here is that with CONFIG_PREEMPT_RT=y, timer callbacks
can be preempted.
Adopt preempt_disable_nested()/preempt_enable_nested() to fix this.
[1]
WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 __seqprop_assert include/linux/seqlock.h:221 [inline]
WARNING: CPU: 0 PID: 16 at ./include/linux/seqlock.h:221 est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93
Modules linked in:
CPU: 0 UID: 0 PID: 16 Comm: ktimers/0 Not tainted syzkaller #0 PREEMPT_{RT,(full)}
Hardware name: Google Google Compute Engine/Google Compute Engine, BIOS Google 07/12/2025
RIP: 0010:__seqprop_assert include/linux/seqlock.h:221 [inline]
RIP: 0010:est_timer+0x6dc/0x9f0 net/core/gen_estimator.c:93
Call Trace:
See more information about CVE-2025-39900 from MITRE CVE dictionary and NIST NVD
NOTE: The following CVSS metrics and score provided are preliminary and subject to review.
| Base Score: | 7.0 |
| Vector String: | CVSS:3.1/AV:L/AC:H/PR:L/UI:N/S:U/C:H/I:H/A:H |
| Version: | 3.1 |
| Attack Vector: | Local |
| Attack Complexity: | High |
| Privileges Required: | Low |
| User Interaction: | None |
| Scope: | Unchanged |
| Confidentiality Impact: | High |
| Integrity Impact: | High |
| Availability Impact: | High |
| Platform | Errata | Release Date |
| Oracle Linux version 10 (kernel-uek) | ELSA-2025-25754 | 2025-11-09 |
| Oracle Linux version 9 (kernel-uek) | ELSA-2025-25754 | 2025-11-09 |
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