VulnerabilityPublished 15 Aug 2026Updated 21 Oct 2026

CVE-2026-72320: Linux kernel · netfilter: nft_lookup: fix catchall element handling with inverted lookups

Affects Linux kernelSource CVE Database V5

Not known to be exploited · CVSS 9.1 Critical · fixed in ef0c7d4b04a0e6ad175323c24bc84e11470dd79d : patch Linux kernel as a priority.

Data as of 26 Oct 2026, 14:05 UTC

CVSS 3.1 base score

9.1Critical

How severe the flaw is on the 0–10 CVSS scale.

EPSS

0.5% chance of exploitation in 30 days – higher than 44% of CVEsExploit Prediction Scoring System: the likelihood attackers will use this flaw soon.

Exploitation: No evidence of active exploitation and no public proof of concept
Automatable: Attackers can reliably automate steps 1–4 of the kill chain
Technical impact: Total control over the software or total information disclosure

CISA SSVC assessment, 2026-10-16.

Patch

Available – fixed in ef0c7d4b04a0e6ad175323c24bc84e11470dd79d, e6107a4c74b54cb33e3bce162a63048ae5a6b198, 238c612357b5a25f03eacf356f95034f8551f218 +2

CVSS:3.1/AV:N/AC:L/PR:N/UI:N/S:U/C:H/I:H/A:N

Attack Vector: Network
Attack Complexity: Low
Privileges Required: None
User Interaction: None
Scope: Unchanged
Confidentiality: High
Integrity: High
Availability: None

Bold values are the worst case: easiest to exploit or largest impact.

Attack Vector: Network: The vulnerable component is bound to the network stack and the set of possible attackers extends beyond the other options listed, up to and including the entire Internet. Such a vulnerability is often termed 'remotely exploitable' and can be thought of as an attack being exploitable at the protocol level one or more network hops away (e.g., across one or more routers).
Attack Complexity: Low: Specialized access conditions or extenuating circumstances do not exist. An attacker can expect repeatable success against the vulnerable component.
Privileges Required: None: The attacker is unauthorized prior to attack, and therefore does not require any access to settings or files to carry out an attack.
User Interaction: None: The vulnerable system can be exploited without any interaction from any user.
Scope: Unchanged: An exploited vulnerability can only affect resources managed by the same security authority. In this case, the vulnerable component and the impacted component are either the same, or both are managed by the same security authority.
Confidentiality: High: There is total loss of confidentiality, resulting in all resources within the impacted component being divulged to the attacker. Alternatively, access to only some restricted information is obtained, but the disclosed information presents a direct, serious impact.
Integrity: High: There is a total loss of integrity, or a complete loss of protection. For example, the attacker is able to modify any/all files protected by the impacted component. Alternatively, only some files can be modified, but malicious modification would present a direct, serious consequence to the impacted component.
Availability: None: There is no impact to availability within the impacted component.

Definitions: FIRST CVSS v3.1 specification.

Exploitation evidence

Disclosed: evidence found.
CVE published 15 Aug 2026
Detectable: no evidence on record.
No public nuclei template indexed
Weaponised: no evidence on record.
No public exploit code indexed in Metasploit or Exploit-DB
Exploited in the wildExploited: no evidence on record.
Not in CISA KEV and no source reports exploitation
Observed by OffSeq MirageSeen by Mirage: no evidence on record.
No attack traffic recorded by OffSeq Mirage sensors

A missing step is not evidence of safety. Sources: cve.org (opens in a new tab), the Metasploit, Exploit-DB and nuclei-templates index as of 26 Oct 2026.

Disclosed: The CVE record is public on cve.org. Its publication is t = 0.
Detectable: A public nuclei template can find exposed instances, for defenders and attackers alike.
Weaponised: Public exploit code exists in Metasploit or Exploit-DB, or CISA SSVC or the CVSS exploit maturity reports a public proof of concept.
Exploited in the wild: CISA KEV lists it, CISA SSVC rates exploitation active, or a source reports attacks.
Observed by OffSeq Mirage: OffSeq Mirage honeypot sensors recorded attack traffic for this CVE, or found exposed hosts without attack traffic.

Moments are spaced evenly, not to scale; a dashed line marks a gap of six months or more. Deltas count from t = 0. Sources that give only a date (CISA KEV, Exploit-DB, or a time of exactly 00:00Z) read “same day” rather than hours. Metasploit modules carry the flaw’s disclosure date, not their release date, and nuclei templates carry no date, so both appear above but not on the timeline.

What to do

Upgrade to a fixed release listed under Affected software.

Affected software

Product	Affected	Fixed in
LinuxLinux	Affected ≥ aaa31047a6d25da0fa101da1ed544e1247949b40, < ef0c7d4b04a0e6ad175323c24bc84e11470dd79d	Fixed in ef0c7d4b04a0e6ad175323c24bc84e11470dd79d
LinuxLinux	Affected ≥ aaa31047a6d25da0fa101da1ed544e1247949b40, < e6107a4c74b54cb33e3bce162a63048ae5a6b198	Fixed in e6107a4c74b54cb33e3bce162a63048ae5a6b198
LinuxLinux	Affected ≥ aaa31047a6d25da0fa101da1ed544e1247949b40, < 238c612357b5a25f03eacf356f95034f8551f218	Fixed in 238c612357b5a25f03eacf356f95034f8551f218
LinuxLinux	Affected ≥ aaa31047a6d25da0fa101da1ed544e1247949b40, < 65d35cb555f40529a9edc6bf4beaa3bee917f015	Fixed in 65d35cb555f40529a9edc6bf4beaa3bee917f015
LinuxLinux	Affected ≥ aaa31047a6d25da0fa101da1ed544e1247949b40, < 0ab8880865f9678eb6174e72c1fc4712e44c745c	Fixed in 0ab8880865f9678eb6174e72c1fc4712e44c745c
LinuxLinux	Affected =5.13	Fixed in–

Description

In the Linux kernel, the following vulnerability has been resolved: netfilter: nft_lookup: fix catchall element handling with inverted lookups nft_lookup_eval() decides whether a lookup matched (`found`) from the direct set lookup and priv->invert before falling back to the catchall element used by interval sets (e.g. nft_set_rbtree) for the open-ended default range. Since `found` is never recomputed after `ext` is replaced by the catchall lookup, inverted lookups (NFT_LOOKUP_F_INV, "!= @set") can wrongly match or wrongly skip the catchall element, producing the wrong verdict. Fold the catchall lookup into `ext` before computing `found`, matching the order already used by nft_objref_map_eval().

References

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