CVE-2023-53635
netfilter: conntrack: fix wrong ct->timeout value
- Published
- Updated
- Reserved
- Assigned by
- Linux
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: conntrack: fix wrong ct->timeout value (struct nf_conn)->timeout is an interval before the conntrack confirmed. After confirmed, it becomes a timestamp. It is observed that timeout of an unconfirmed conntrack: - Set by calling ctnetlink_change_timeout(). As a result, `nfct_time_stamp` was wrongly added to `ct->timeout` twice. - Get by calling ctnetlink_dump_timeout(). As a result, `nfct_time_stamp` was wrongly subtracted. Call Trace: <TASK> dump_stack_lvl ctnetlink_dump_timeout __ctnetlink_glue_build ctnetlink_glue_build __nfqnl_enqueue_packet nf_queue nf_hook_slow ip_mc_output ? __pfx_ip_finish_output ip_send_skb ? __pfx_dst_output udp_send_skb udp_sendmsg ? __pfx_ip_generic_getfrag sock_sendmsg Separate the 2 cases in: - Setting `ct->timeout` in __nf_ct_set_timeout(). - Getting `ct->timeout` in ctnetlink_dump_timeout(). Pablo appends: Update ctnetlink to set up the timeout _after_ the IPS_CONFIRMED flag is set on, otherwise conntrack creation via ctnetlink breaks. Note that the problem described in this patch occurs since the introduction of the nfnetlink_queue conntrack support, select a sufficiently old Fixes: tag for -stable kernel to pick up this fix.
Timeline
ID reserved
By Linux
Published
- 12 months later
· 12 months later
Record updated
Changes after publication (a new score, a public exploit, EPSS crossing 1, 10 or 50 %, leaving KEV) are kept since November 2026; earlier ones are not known.
Scores
| Scored by | CVSS | Score | Vector |
|---|---|---|---|
| LinuxCNA (assigner) | 3.1 | High8.2 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:L/A:H |
| NVDNVD · Modified | 3.1 | Medium5.5 | CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.43% · top 62% of all CVEs (7 Nov 2026)
- CISA SSVC
- Exploitation: none · Automatable: yes · Technical impact: partial
The list uses the assigner's score when there is one, then CISA's, then NVD's: High 8.2.
Affected products
- affected a4b4766c3cebb4018167e06b863d8e95b7274757 – < 80c5ba0078e20d926d11d0778f9a43902664ebf0
- affected a4b4766c3cebb4018167e06b863d8e95b7274757 – < ff5e4ac8dd7be7f1faba955c5779a68571eeb0f8
- affected a4b4766c3cebb4018167e06b863d8e95b7274757 – < f612ae1ab4793701caf39386fb3b7f4b3ef44e48
- affected a4b4766c3cebb4018167e06b863d8e95b7274757 – < 73db1b8f2bb6725b7391e85aab41fdf592b3c0c1
- affected 4.4
- unaffected < 4.4
- unaffected 6.1.28 – ≤ 6.1.*
- unaffected 6.2.15 – ≤ 6.2.*
- unaffected 6.3.2 – ≤ 6.3.*
- unaffected 6.4 – ≤ *
References (4)
- https://git.kernel.org/stable/c/80c5ba0078e20d926d11d0778f9a43902664ebf0 (opens in a new tab)
- https://git.kernel.org/stable/c/ff5e4ac8dd7be7f1faba955c5779a68571eeb0f8 (opens in a new tab)
- https://git.kernel.org/stable/c/f612ae1ab4793701caf39386fb3b7f4b3ef44e48 (opens in a new tab)
- https://git.kernel.org/stable/c/73db1b8f2bb6725b7391e85aab41fdf592b3c0c1 (opens in a new tab)
Sources
The same CVE in the primary databases and aggregators, to check against.
- CVE.org record (opens in a new tab)
- CVE List JSON (GitHub) (opens in a new tab)
- NVD (opens in a new tab)
- FIRST EPSS (opens in a new tab)
- OSV.dev (opens in a new tab)
- GitHub Advisories (opens in a new tab)
- CIRCL Vulnerability-Lookup (opens in a new tab)
Badge for a README or a ticket
[](https://trackcve.app/cve/CVE-2023-53635)Record last updated .