netfilter: conntrack: dccp: copy entire header to stack buffer, not just basic one
Published Sep 16, 2025
8.2
HIGHCVSS 3.1
EPSS 0.28%
Description
Eric Dumazet says: nf_conntrack_dccp_packet() has an unique:
dh = skb_header_pointer(skb, dataoff, sizeof(_dh), &_dh);
And nothing more is 'pulled' from the packet, depending on the content. dh->dccph_doff, and/or dh->dccph_x ...) So dccp_ack_seq() is happily reading stuff past the _dh buffer.
BUG: KASAN: stack-out-of-bounds in nf_conntrack_dccp_packet+0x1134/0x11c0 Read of size 4 at addr ffff000128f66e0c by task syz-executor.2/29371 [..]
Fix this by increasing the stack buffer to also include room for the extra sequence numbers and all the known dccp packet type headers, then pull again after the initial validation of the basic header.
While at it, mark packets invalid that lack 48bit sequence bit but where RFC says the type MUST use them.
Compile tested only.
v2: first skb_header_pointer() now needs to adjust the size to only pull the generic header. (Eric)
Heads-up: I intend to remove dccp conntrack support later this year.
Affected products
-
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version StatusaffectedConstraints
- Version
-
- Version 2.6.26StatusaffectedConstraints-
- Version 0StatusunaffectedConstraints<2.6.26
- Version 5.10.188StatusunaffectedConstraints<=5.10.*
- Version 5.15.121StatusunaffectedConstraints<=5.15.*
- Version 5.4.251StatusunaffectedConstraints<=5.4.*
- Version 6.1.39StatusunaffectedConstraints<=6.1.*
- Version 6.3.13StatusunaffectedConstraints<=6.3.*
- Version 6.4.4StatusunaffectedConstraints<=6.4.*
- Version 6.5StatusunaffectedConstraints<=*
- Version
Default status is the baseline for the product, each version can override it (e.g. patched versions marked unaffected).
| Vendor | Product | Default status | Versions | ||||||||||||||||||||||||||||||
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| Linux | Linux | unaffected |
| ||||||||||||||||||||||||||||||
| Linux | Linux | affected |
|
- ≥ 2.6.26 · < 5.4.251
- ≥ 5.5 · < 5.10.188
- ≥ 5.11 · < 5.15.121
- ≥ 5.16 · < 6.1.39
- ≥ 6.2 · < 6.3.13
- ≥ 6.4 · < 6.4.4
No data.
Red Hat Enterprise Linux 10
kernel
Not affected
Red Hat Enterprise Linux 6
kernel
Out of support scope
Red Hat Enterprise Linux 7
kernel
Fix deferred
Red Hat Enterprise Linux 7
kernel-rt
Fix deferred
Red Hat Enterprise Linux 8
kernel
Fix deferred
Red Hat Enterprise Linux 8
kernel-rt
Fix deferred
Red Hat Enterprise Linux 9
kernel
Fix deferred
Red Hat Enterprise Linux 9
kernel-rt
Fix deferred
| Product | Package | State | Advisory |
|---|---|---|---|
| Red Hat Enterprise Linux 10 | kernel | Not affected | n/a |
| Red Hat Enterprise Linux 6 | kernel | Out of support scope | n/a |
| Red Hat Enterprise Linux 7 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 7 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 8 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 8 | kernel-rt | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel | Fix deferred | n/a |
| Red Hat Enterprise Linux 9 | kernel-rt | Fix deferred | n/a |
No package ranges for this CVE.
Remediation
Red Hat statement
This vulnerability is rated Moderate for Red Hat Enterprise Linux. The flaw is a stack-out-of-bounds read in the netfilter DCCP connection tracking module. Exploitation requires an attacker to send specially crafted DCCP packets to a system with the `nf_conntrack_dccp` module loaded. The vulnerability's impact is primarily on availability, since a malformed packet can lead to a warning or panic, though it can also pose a potential (though unlikely) risk to confidentiality, since kernel stack values could be exposed indirectly through side channels or other error-dependent behaviors.
References (12)
- https://access.redhat.com/security/cve/CVE-2023-53333 Vendor Advisory
- https://bugzilla.redhat.com/show_bug.cgi?id=2395885 Issue Tracking
- https://git.kernel.org/stable/c/26bd1f210d3783a691052c51d76bb8a8bbd24c67 Patch
- https://git.kernel.org/stable/c/337fdce450637ea663bc816edc2ba81e5cdad02e Patch
- https://git.kernel.org/stable/c/5c618daa5038712c4a4ef8923905a2ea1b8836a1 Patch
- https://git.kernel.org/stable/c/8c0980493beed3a80d6329c44ab293dc8c032927 Patch
- https://git.kernel.org/stable/c/9bdcda7abaf22f6453e5b5efb7eb4e524095d5d8 Patch
- https://git.kernel.org/stable/c/c052797ac36813419ad3bfa54cb8615db4b41f15 Patch
- https://git.kernel.org/stable/c/ff0a3a7d52ff7282dbd183e7fc29a1fe386b0c30 Patch
- https://lore.kernel.org/linux-cve-announce/2025091646-CVE-2023-53333-f2b8@gregkh/T
- https://nvd.nist.gov/vuln/detail/CVE-2023-53333
- https://www.cve.org/CVERecord?id=CVE-2023-53333
Change history (0)
No recorded changes yet.