Threadlinqs IntelligenceStart free

VulnerabilityCVE-2026-23111Published 2026-02-13

CVE-2026-23111 — Linux

highPublic exploit11 PoC repos

As of 2026-09-08, CVE-2026-23111 is a HIGH-severity vulnerability in Linux, CVSS v3.1 7.8, EPSS 0.5% (40.9th percentile). Threadlinqs Intelligence links 1 tracked threat campaign to CVE-2026-23111, most recently “CVE-2026-23111: Linux Kernel nf_tables Use-After-Free Enables Local Privilege Escalation and Container Escape”.

CVSS v3.1
7.8/10High
EPSS
0.5%Higher than 40.9% of scored CVEs
CISA KEV
NoNot in the KEV catalog
Tracked threats
1Campaigns referencing it
Priority
7.5/10Threadlinqs triage score
Published
Updated 2026-09-08
CVSS v3.1 7.8 (HIGH) · EPSS 0.5% (higher than 40.9% of all scored CVEs) · Priority 7.5/10 · Published 2026-02-13

Last updated:

What is CVE-2026-23111?

In the Linux kernel, the following vulnerability has been resolved: netfilter: nf_tables: fix inverted genmask check in nft_map_catchall_activate() nft_map_catchall_activate() has an inverted element activity check compared to its non-catchall counterpart nft_mapelem_activate() and compared to what is logically required. nft_map_catchall_activate() is called from the abort path to re-activate catchall map elements that were deactivated during a failed transaction. It should skip elements that are already active (they don't need re-activation) and process elements that are inactive (they need to be restored). Instead, the current code does the opposite: it skips inactive elements and processes active ones. Compare the non-catchall activate callback, which is correct: nft_mapelem_activate(): if (nft_set_elem_active(ext, iter->genmask)) return 0; /* skip active, process inactive */ With the buggy catchall version: nft_map_catchall_activate(): if (!nft_set_elem_active(ext, genmask)) continue; /* skip inactive, process active */ The consequence is that when a DELSET operation is aborted, nft_setelem_data_activate() is never called for the catchall element. For NFT_GOTO verdict elements, this means nft_data_hold() is never called to restore the chain->use reference count. Each abort cycle permanently decrements chain->use. Once chain->use reaches zero, DELCHAIN succeeds and frees the chain while catchall verdict elements still reference it, resulting in a use-after-free. This is exploitable for local privilege escalation from an unprivileged user via user namespaces + nftables on distributions that enable CONFIG_USER_NS and CONFIG_NF_TABLES. Fix by removing the negation so the check matches nft_mapelem_activate(): skip active elements, process inactive ones.

The record classifies CVE-2026-23111 under weakness classes CWE-416, CWE-672. Its CVSS v3 base vector states that the flaw requires local access to the host, needs low-privilege credentials, needs no user interaction, and has high impact on confidentiality, integrity, availability. 1 affected-product entry is recorded, across 1 vendor, listed below. The identifier was first published 239 days ago.

Severity and exploitation probability

CVSS v3.1 base score
7.8 — HIGH
CVSS:3.1/AV:L/AC:L/PR:L/UI:N/S:U/C:H/I:H/A:H
EPSS (FIRST)
0.5% probability of exploitation in the next 30 days, higher than 40.9% of all scored CVEs
CISA KEV
Not listed in the CISA Known Exploited Vulnerabilities catalog
Threadlinqs priority
7.5/10 — a Threadlinqs composite of the CVSS base score, the EPSS percentile and public exploit availability
Published
2026-02-13, last modified 2026-09-08

Is CVE-2026-23111 being exploited?

Weaponised exploit code for CVE-2026-23111 is publicly available. 11 public proof-of-concept repositories are tracked for this identifier. It currently carries a trending score of 23 in the Threadlinqs vulnerability feed.

Affected products and versions

How to fix CVE-2026-23111

No vendor patch reference has been recorded for CVE-2026-23111 in the tracked sources. Follow the references below for a fix, and treat the products listed above as exposed until the vendor states otherwise.

Threat activity tracking CVE-2026-23111

1 tracked threat in the Threadlinqs corpus references CVE-2026-23111, either in the campaign’s CVE list or as an indicator on the campaign record.

Sources

Enriched from CVE.org, FIRST EPSS, GitHub Security Advisories, public proof-of-concept repositories. Last verified by Threadlinqs on .

Other references

Showing 5 of 6 recorded references.