CVE-2026-72247netfilter: nf_conncount: fix zone comparison in tuple dedup
- 7.5HighCVSS base score
- 0.70%Exploitation in 30 daysEPSS · top 46% of all CVEs
- NoKnown exploitednot in CISA's KEV catalog
- NonePublic exploitsnone known yet
Description
In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_conncount: fix zone comparison in tuple dedup The "already exists" dedup logic in __nf_conncount_add() decides whether a connection has already been counted and can be skipped instead of incrementing the connlimit count. It compares the conntrack zone of a list entry with the zone of the connection being added using nf_ct_zone_id() and nf_ct_zone_equal(), passing conn->zone.dir or zone->dir as the direction argument. Those helpers take enum ip_conntrack_dir values: IP_CT_DIR_ORIGINAL is 0 and IP_CT_DIR_REPLY is 1. However, zone->dir is a u8 bitmask: NF_CT_ZONE_DIR_ORIG is 1, NF_CT_ZONE_DIR_REPL is 2 and NF_CT_DEFAULT_ZONE_DIR is 3. Passing that bitmask as the enum direction shifts the meaning of every non-zero value. An ORIG-only zone passes 1 and is tested as REPLY, while REPL-only and default zones pass 2 or 3 and test bits beyond the valid direction range. In those cases nf_ct_zone_id() can fall back to NF_CT_DEFAULT_ZONE_ID instead of using the real zone id, so different zones can be treated as equal and dedup collapses to tuple equality alone. nf_conncount stores and compares the original-direction tuple for a connection. If an skb already has an attached conntrack entry, get_ct_or_tuple_from_skb() explicitly copies ct->tuplehash[IP_CT_DIR_ORIGINAL].tuple, regardless of the packet's ctinfo. Therefore the zone comparison in the tuple dedup path must use IP_CT_DIR_ORIGINAL as well; the zone direction bitmask describes where a zone id applies, not which direction this conncount tuple represents. Fix the two dedup comparisons by passing IP_CT_DIR_ORIGINAL directly. Do not special-case NF_CT_DEFAULT_ZONE_DIR and do not compare raw zone ids: using the existing helpers with IP_CT_DIR_ORIGINAL preserves the direction-aware NF_CT_DEFAULT_ZONE_ID fallback. A default bidirectional zone contains the ORIG bit, so it naturally returns the real zone id; reply-only zones continue to fall back for original-direction tuple comparisons.
Timeline
ID reserved
By Linux
- 6 days later
· 6 days later
Published
- 2 months later
· 2 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 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
| NVDNVD · Received | 3.1 | High7.5 | CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:N/I:N/A:H |
- EPSS (exploitation in 30 days)
- 0.70% · top 46% of all CVEs (14 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 7.5.
Affected products
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < 82fc35e0da9a91db9a034f8311f18f77a599ae3f
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < 78b5d6dbc860776161f9e9206b06ff8a01f531ab
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < 4f30a89c0ed2418719a1144881c2635b940b543d
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < 7bdc3c0985ecf17b957811fedcc684acdf698acc
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < 35a56e2a46b90e6bd4ca816b80e9cb8d20dfc3ce
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < 3cd9a5792cbea81139c24320986dd0db69e9b5d0
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < 6ff07ac5405bea4d4ead3559fc123f987576424a
- affected 21ba8847f857028dc83a0f341e16ecc616e34740 – < f62c41b4910e65da396ec9a8c40c1fe7fe82e449
- affected 525e1dffed8711973f77412729621098a95238e5
- affected 75af3d78168e654a5cd8bbc4c774f97be836165f
- affected 4.14.92 – < 4.15
- affected 4.18
- unaffected < 4.18
- unaffected 5.10.261 – ≤ 5.10.*
- unaffected 5.15.212 – ≤ 5.15.*
- unaffected 6.1.178 – ≤ 6.1.*
- unaffected 6.6.145 – ≤ 6.6.*
- unaffected 6.12.97 – ≤ 6.12.*
- unaffected 6.18.40 – ≤ 6.18.*
- unaffected 7.1.5 – ≤ 7.1.*
- unaffected 7.2 – ≤ *
References
References8
- https://git.kernel.org/stable/c/82fc35e0da9a91db9a034f8311f18f77a599ae3f (opens in a new tab)
- https://git.kernel.org/stable/c/78b5d6dbc860776161f9e9206b06ff8a01f531ab (opens in a new tab)
- https://git.kernel.org/stable/c/4f30a89c0ed2418719a1144881c2635b940b543d (opens in a new tab)
- https://git.kernel.org/stable/c/7bdc3c0985ecf17b957811fedcc684acdf698acc (opens in a new tab)
- https://git.kernel.org/stable/c/35a56e2a46b90e6bd4ca816b80e9cb8d20dfc3ce (opens in a new tab)
- https://git.kernel.org/stable/c/3cd9a5792cbea81139c24320986dd0db69e9b5d0 (opens in a new tab)
- https://git.kernel.org/stable/c/6ff07ac5405bea4d4ead3559fc123f987576424a (opens in a new tab)
- https://git.kernel.org/stable/c/f62c41b4910e65da396ec9a8c40c1fe7fe82e449 (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)
- EUVD EUVD-2026-59146 (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)
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[](https://cveledger.app/cve/CVE-2026-72247)Record last updated .