5.5 CVE-2025-38001
Enriched by CISA Patch Exploit
In the Linux kernel, the following vulnerability has been resolved:
net_sched: hfsc: Address reentrant enqueue adding class to eltree twice
Savino says:
"We are writing to report that this recent patch
(141d34391abbb315d68556b7c67ad97885407547) [1]
can be bypassed, and a UAF can still occur when HFSC is utilized with
NETEM.
The patch only checks the cl->cl_nactive field to determine whether
it is the first insertion or not [2], but this field is only
incremented by init_vf [3].
By using HFSC_RSC (which uses init_ed) [4], it is possible to bypass the
check and insert the class twice in the eltree.
Under normal conditions, this would lead to an infinite loop in
hfsc_dequeue for the reasons we already explained in this report [5].
However, if TBF is added as root qdisc and it is configured with a
very low rate,
it can be utilized to prevent packets from being dequeued.
This behavior can be exploited to perform subsequent insertions in the
HFSC eltree and cause a UAF."
To fix both the UAF and the infinite loop, with netem as an hfsc child,
check explicitly in hfsc_enqueue whether the class is already in the eltree
whenever the HFSC_RSC flag is set.
[1] https://web.git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=141d34391abbb315d68556b7c67ad97885407547
[2] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1572
[3] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L677
[4] https://elixir.bootlin.com/linux/v6.15-rc5/source/net/sched/sch_hfsc.c#L1574
[5] https://lore.kernel.org/netdev/8DuRWwfqjoRDLDmBMlIfbrsZg9Gx50DHJc1ilxsEBNe2D6NMoigR_eIRIG0LOjMc3r10nUUZtArXx4oZBIdUfZQrwjcQhdinnMis_0G7VEk=@willsroot.io/T/#u
https://nvd.nist.gov/vuln/detail/CVE-2025-38001
Categories
CWE-835 : Loop with Unreachable Exit Condition ('Infinite Loop')
The product contains an iteration or loop with an exit condition that cannot be reached, i.e., an infinite loop. Automated static analysis, commonly referred to as Static Application Security Testing (SAST), can find some instances of this weakness by analyzing source code (or binary/compiled code) without having to execute it. Typically, this is done by building a model of data flow and control flow, then searching for potentially-vulnerable patterns that connect "sources" (origins of input) with "sinks" (destinations where the data interacts with external components, a lower layer such as the OS, etc.) Chain: library for implementing Profinet devices does not check an input for a loop condition (CWE-606), allowing an infinite loop (CWE-835) via a crafted RPC packet Chain: an operating system does not properly process malformed Open Shortest Path First (OSPF) Type/Length/Value Identifiers (TLV) (CWE-703), which can cause the process to enter an infinite loop (CWE-835) A Python machine communication platform did not account for receiving a malformed packet with a null size, causing the receiving function to never update the message buffer and be caught in an infinite loop. Chain: off-by-one error (CWE-193) leads to infinite loop (CWE-835) using invalid hex-encoded characters. Chain: self-referential values in recursive definitions lead to infinite loop. NULL UDP packet is never cleared from a queue, leading to infinite loop. Chain: web browser crashes due to infinite loop - "badlooping logic [that relies on] floating point math [CWE-1339] to exitthe loop [CWE-835]" Floating point conversion routine cycles back and forth between two different values. Floating point conversion routine cycles back and forth between two different values. Chain: improperly clearing a pointer in a linked list leads to infinite loop. Chain: an integer overflow (CWE-190) in the image size calculation causes an infinite loop (CWE-835) which sequentially allocates buffers without limits (CWE-1325) until the stack is full. Chain: A denial of service may be caused by an uninitialized variable (CWE-457) allowing an infinite loop (CWE-835) resulting from a connection to an unresponsive server.
References
416baaa9-dc9f-4396-8d5f-8c081fb06d67 Patch
af854a3a-2127-422b-91ae-364da2661108 Patch
| https://lists.debian.org/debian-lts-announce/2025/10/msg00007.html Third Party Advisory |
| https://lists.debian.org/debian-lts-announce/2025/10/msg00008.html Third Party Advisory |
| https://syst3mfailure.io/rbtree-family-drama/ Third Party Advisory |
AFFECTED (from MITRE)
| Vendor | Product | Versions |
|---|---|---|
| Linux | Linux |
|
| Linux | Linux |
|
| © 2022 The MITRE Corporation. This work is reproduced and distributed with the permission of The MITRE Corporation. | ||
CPE
| cpe | start | end |
|---|---|---|
| Configuration 1 | ||
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 5.0.1 | < 5.4.294 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 5.5 | < 5.10.238 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 5.11 | < 5.15.185 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 5.16 | < 6.1.141 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.2 | < 6.6.93 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.7 | < 6.12.32 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.13 | < 6.14.10 |
| cpe:2.3:o:linux:linux_kernel:*:*:*:*:*:*:*:* | >= 6.15 | < 6.15.1 |
| cpe:2.3:o:linux:linux_kernel:5.0:-:*:*:*:*:*:* | ||
| cpe:2.3:o:linux:linux_kernel:5.0:rc3:*:*:*:*:*:* | ||
| cpe:2.3:o:linux:linux_kernel:5.0:rc4:*:*:*:*:*:* | ||
| cpe:2.3:o:linux:linux_kernel:5.0:rc5:*:*:*:*:*:* | ||
| cpe:2.3:o:linux:linux_kernel:5.0:rc6:*:*:*:*:*:* | ||
| cpe:2.3:o:linux:linux_kernel:5.0:rc7:*:*:*:*:*:* | ||
| cpe:2.3:o:linux:linux_kernel:5.0:rc8:*:*:*:*:*:* | ||
| Configuration 2 | ||
| cpe:2.3:o:debian:debian_linux:11.0:*:*:*:*:*:*:* | ||
| cpe:2.3:o:debian:debian_linux:12.0:*:*:*:*:*:*:* | ||
REMEDIATION
Patch
EXPLOITS
Exploit-db.com
| id | description | date | |
|---|---|---|---|
| No known exploits | |||
POC Github
| Url |
|---|
| https://github.com/0xdevil/CVE-2025-38001 |
| https://github.com/aexdyhaxor/CVE-2025-38001 |
Other Nist (github, ...)
| Url |
|---|
| No known exploits |
CAPEC
Common Attack Pattern Enumerations and Classifications
| id | description | severity |
|---|---|---|
| No entry | ||
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