CVE-2025-39703
- Source
- https://nvd.nist.gov/vuln/detail/CVE-2025-39703
- Import Source
- https://storage.googleapis.com/osv-test-cve-osv-conversion/osv-output/CVE-2025-39703.json
- JSON Data
- https://api.test.osv.dev/v1/vulns/CVE-2025-39703
- Downstream
- Related
- Published
- 2025-09-05T17:21:09Z
- Modified
- 2025-10-10T18:15:08.637453Z
- Summary
- net, hsr: reject HSR frame if skb can't hold tag
- Details
-
In the Linux kernel, the following vulnerability has been resolved:
net, hsr: reject HSR frame if skb can't hold tag
Receiving HSR frame with insufficient space to hold HSR tag in the skb can result in a crash (kernel BUG):
[ 45.390915] skbuff: skbunderpanic: text:ffffffff86f32cac len:26 put:14 head:ffff888042418000 data:ffff888042417ff4 tail:0xe end:0x180 dev:bridgeslave1 [ 45.392559] ------------[ cut here ]------------ [ 45.392912] kernel BUG at net/core/skbuff.c:211! [ 45.393276] Oops: invalid opcode: 0000 [#1] SMP DEBUGPAGEALLOC KASAN NOPTI [ 45.393809] CPU: 1 UID: 0 PID: 2496 Comm: reproducer Not tainted 6.15.0 #12 PREEMPT(undef) [ 45.394433] Hardware name: QEMU Standard PC (i440FX + PIIX, 1996), BIOS rel-1.16.3-0-ga6ed6b701f0a-prebuilt.qemu.org 04/01/2014 [ 45.395273] RIP: 0010:skbpanic+0x15b/0x1d0
<snip registers, remove unreliable trace>
[ 45.402911] Call Trace: [ 45.403105] <IRQ> [ 45.404470] skbpush+0xcd/0xf0 [ 45.404726] brdevqueuepushxmit+0x7c/0x6c0 [ 45.406513] brforwardfinish+0x128/0x260 [ 45.408483] _brforward+0x42d/0x590 [ 45.409464] maybedeliver+0x2eb/0x420 [ 45.409763] brflood+0x174/0x4a0 [ 45.410030] brhandleframefinish+0xc7c/0x1bc0 [ 45.411618] brhandleframe+0xac3/0x1230 [ 45.413674] _netifreceiveskbcore.constprop.0+0x808/0x3df0 [ 45.422966] _netifreceiveskbonecore+0xb4/0x1f0 [ 45.424478] _netifreceiveskb+0x22/0x170 [ 45.424806] processbacklog+0x242/0x6d0 [ 45.425116] _napipoll+0xbb/0x630 [ 45.425394] netrxaction+0x4d1/0xcc0 [ 45.427613] handlesoftirqs+0x1a4/0x580 [ 45.427926] do_softirq+0x74/0x90 [ 45.428196] </IRQ>
This issue was found by syzkaller.
The panic happens in brdevqueuepushxmit() once it receives a corrupted skb with ETH header already pushed in linear data. When it attempts the skbpush() call, there's not enough headroom and skbpush() panics.
The corrupted skb is put on the queue by HSR layer, which makes a sequence of unintended transformations when it receives a specific corrupted HSR frame (with incomplete TAG).
Fix it by dropping and consuming frames that are not long enough to contain both ethernet and hsr headers.
Alternative fix would be to check for enough headroom before skbpush() in brdevqueuepush_xmit().
In the reproducer, this is injected via AF_PACKET, but I don't easily see why it couldn't be sent over the wire from adjacent network.
Further Details:
In the reproducer, the following network interface chain is set up:
┌────────────────┐ ┌────────────────┐ │ veth0tohsr ├───┤ hsrslave0 ┼───┐ └────────────────┘ └────────────────┘ │ │ ┌──────┐ ├─┤ hsr0 ├───┐ │ └──────┘ │ ┌────────────────┐ ┌────────────────┐ │ │┌────────┐ │ veth1tohsr ┼───┤ hsrslave1 ├───┘ └┤ │ └────────────────┘ └────────────────┘ ┌┼ bridge │ ││ │ │└────────┘ │ ┌───────┐ │ │ ... ├──────┘ └───────┘
To trigger the events leading up to crash, reproducer sends a corrupted HSR fr ---truncated---
- References
-
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- https://git.kernel.org/stable/c/3ae272ab523dd6bdc26e879027ed79feac9dd1b3
- https://git.kernel.org/stable/c/61009439e4bd8d74e705ee15940760321be91d8a
- https://git.kernel.org/stable/c/7af76e9d18a9fd6f8611b3313c86c190f9b6a5a7
- https://git.kernel.org/stable/c/8d9bc4a375a1ba05f7dfa0407de8e510ab9bd14d
- https://git.kernel.org/stable/c/acd69b597bd3f76d3b3d322b84082226c00eeaa4
- https://git.kernel.org/stable/c/b117c41b00902c1a7e24347c405cb82504aeae0b
- https://git.kernel.org/stable/c/b640188b8a6690e685939053c7efdbc7818b5f4e
Affected packages
Git / git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
Affected ranges
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introducedf6442ee08fe66c8e45c4f246531a2aaf4f17a7a7Fixed8d9bc4a375a1ba05f7dfa0407de8e510ab9bd14d
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced48b491a5cc74333c4a6a82fe21cea42c055a3b0bFixed3ae272ab523dd6bdc26e879027ed79feac9dd1b3
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced48b491a5cc74333c4a6a82fe21cea42c055a3b0bFixedb640188b8a6690e685939053c7efdbc7818b5f4e
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced48b491a5cc74333c4a6a82fe21cea42c055a3b0bFixedb117c41b00902c1a7e24347c405cb82504aeae0b
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced48b491a5cc74333c4a6a82fe21cea42c055a3b0bFixedacd69b597bd3f76d3b3d322b84082226c00eeaa4
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced48b491a5cc74333c4a6a82fe21cea42c055a3b0bFixed61009439e4bd8d74e705ee15940760321be91d8a
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced48b491a5cc74333c4a6a82fe21cea42c055a3b0bFixed7af76e9d18a9fd6f8611b3313c86c190f9b6a5a7
- Type
- GIT
- Repo
- https://git.kernel.org/pub/scm/linux/kernel/git/stable/linux.git
- Events
-
Introduced4ffd1d4a6b306ff69cbe412d2c54d2dd349ff436
Affected versions
v5.*
v6.*
Linux / Kernel
Package
- Name
- Kernel
Affected ranges
- Type
- ECOSYSTEM
- Events
-
Introduced0Unknown introduced version / All previous versions are affectedFixed5.10.241
- Type
- ECOSYSTEM
- Events
-
Introduced5.11.0Fixed5.15.190
- Type
- ECOSYSTEM
- Events
-
Introduced5.13.0Fixed6.1.149
- Type
- ECOSYSTEM
- Events
-
Introduced5.16.0Fixed6.6.103
- Type
- ECOSYSTEM
- Events
-
Introduced6.2.0Fixed6.12.44
- Type
- ECOSYSTEM
- Events
-
Introduced6.7.0Fixed6.16.4